Tài liệu Worldwide Training pptx

Cisco Systems
Worldwide Training
Standard Telephony Features
Glossary









Standard Telephony Features Glossary
__________________________________________

1 World Wide Training Standard Telephony Features - 10/7/01 3:46 PM
Introduction to Document
This document contains a glossary of the features and terminology of standard
telephony.
Objective
Upon completion of this unit you should be able to:
Identify and describe the features of standard telephony
A
ACD Automatic Call Distribution – there are many different models for ACD. Low-
end ACD is minimal queuing capability for a station or group of stations with little or
no reporting/monitoring. Low to Mid-level ACD will usually include more detailed
reports and other ACD features such as Silent Monitor, overflow queuing and
messaging. High-end ACD will generally include features like Skills based routing,
Time-of-day routing, Agent-Supervisor communications, elaborate/customizable
report capabilities, CTI interfaces for database lookups, IVR integration. In addition

there is usually support for large numbers of agents and Supervisors have extensive
monitoring, management and reporting capabilities.
ADPCM - Adaptive Differential Pulse Code Modulation. An encoding technique,
standardized by the CCITT, that allows a 4kHz voice channel to be carried within a
32Kb/s digital channel. The technique uses 3 or 4 bits to describe the difference
between two samples, taken at a sampling rate of 8,000 times a second.
A-Law - A companding algorithm used as the CEPT standard for DS-0 PCM speech
companding. (See Mµ-Law)
AMI Alternate Mark Inversion is a T1 line coding method. This is the older of the
two commonly available. See Line Coding – T1. See Also B8ZS.
Amplifier is an electronic device that strengthens a signal.
Amplitude is the high point of the wave in an analog signal.
Analog Telephones sometimes referred to as 2500 Sets. Analog phones usually
interface to analog station cards in the PBX. In some PBX’s the analog station can
access PBX features through the use of Feature Access Codes. For example; Flash * 6
might be used to signal to the PBX that the analog station wishes to transfer the call it
is currently in progress with. Other codes can identify Conference, Pickup, Park and
so on. More advanced analog sets might have buttons that can be configured to send
the codes ‘automatically’ thus simplifying the user interface. On some PBX systems
the digital phones have access to features by pressing a Feature button or by pressing
a flash key and then entering the same access code as used by analog phones. (See
also Flash and Digital Telephones)
ANI (See Automatic Number Identification)
Standard Telephony Features Glossary
__________________________________________

2 World Wide Training Standard Telephony Features - 10/7/01 3:46 PM
Attendant Console a multi-line phone (physical or softphone) that can access
incoming or outgoing trunks to route calls to subscribers. PBX manufacturers
generally list several Attendant Console features such as Attendant Recall, Attendant

Hold, Attendant login and so on…
Auto Answer If this feature is programmed on the template, it will cause the phone to
go off-hook (speakerphone) automatically when an incoming call is received.
Auto Attendant is a device that answers callers with a digital recording, and allows
callers to route themselves to an extension through touch-tone input in response to a
voice prompt.
Automatic Callback allows internal users who placed a call to a busy or unanswered
internal telephone to be called back automatically when the called telephone becomes
available. When a user activates automatic callback, the system monitors the called
telephone. When the called telephone becomes available to receive a call, the system
originates the automatic callback call. The originating party receives priority ringing.
The calling party then lifts the handset and the called party receives the same ringing
provided on the original call.
Automatic Call Distribution is provided through groups of employees who serve
customers using telephone, facsimile, Email, the Internet, or remote video links to
provide more convenient sales, service or billing operations. When managed well,
these centers can serve customers quickly, efficiently and cost-effectively. Center
products allow customers in an enterprise to:
1. Retain its customer base through fast and efficient customer response
2. Cater to the needs and preferences of its various customer segments
3. Offer its customers new ways of transacting business
Automatic Camp On is the ability to camp on to a busy station or circuit without the
requirement to invoke a feature access code. On some systems this was allowed from
either/both internal and external callers. For example a user calls a DID number and
hears a standard busy signal if the caller does not hang up within a predefined time
period the system would generate a camp on tone and the call is effectively held for
that station until the phone becomes available. This could be configured such that for
internal callers the calling station could hang up and when the called station become
available the system would issue a call-back ring to the calling station and ring
through to the called station. An occasional situation arose where the called station

did not become available for so long that the caller forgot they were camped on and
would ‘answer’ the phone as if it were a new call coming to them.
Automatic Number Identification ANI is the ability to send/receive the calling
number. Some systems can route calls based on this information by making a match in
a database and following predefined routing rules. (See also DNIS)
Automatic Route Selection ARS - Automatic Route Selection (ARS) simplifies local
and long distance dialing by automatically selecting the most convenient and cost-
effective route and by inserting and/or deleting the proper routing digits.
Authorization Code May be referred to as Checked/Verified, Un-Checked/Un-
Verified, Forced, Variable and other descriptions. This code may be used to
Standard Telephony Features Glossary
__________________________________________

3 World Wide Training Standard Telephony Features - 10/7/01 3:46 PM
1. control access to features.
2. identify user for charge-back purposes.
3. prohibit or limit access to external trunks or facilities.
4. support input of user defined codes; wrap-up codes for ACD, client/matter
codes for law firms and so on. The codes are stored in the CDR/SMDR
database and used to track reason for calls or bill back to clients.

B
B8ZS - Bipolar 8 Zero Substitution is a technique used with DS-1 signals in order
to maintain ones density, where a special code is substituted for eight consecutive
zeros and marked by two bipolar violations. The use of B8ZS allows the use of a full
64kb/s DS-0 for data transmission. This is called ‘clear channel’. Not compatible with
older "AMI" equipment. (Referred to Bipolar 8 Zero Substitution by early AT&T
ref.). The receiver must have the ability to recognize the code and return it to the same
bit sequence (8 zero’s). Applied against all 24 DS-Os on a DS-1, the effective data
throughput of the DS-1 facility is increased with B8ZS from 1.344 Mbps to 1.536

Mbps, a 14% increase in throughput.
Bandwidth is a measure of the communication capacity or data transmission rate of a
Circuit. The total frequency spectrum (in Hertz - cycles per second) that is allocated
or available to a channel, or the amount of data that can be carried (in bits per second)
by a channel.
Basic Rate Interface (BRI) is an ISDN offering that allows two 64kbps and one
16kbps channels to be carried over 1 typical single pair of copper wires. This is the
type of service that would be used to connect a small branch or home office to a
remote network. Through the use of BONDING (Bandwidth on Demand) the two
64kbps channels can be combined to create more bandwidth as it becomes necessary.
B Channel Bearer Channel. Is one of the multiple user channels on an ISDN circuit.
Used to carry user's voice/data
Bell Labs is the basic research facility that was AT&T's primary research facility.
Bell Labs was spun off with Lucent Technologies. Many very important discoveries
have been made at Bell Labs including the transistor, communications theory, and
radio astronomy.
Bellcore BELL COmmunications REsearch. See Telcordia. The research and
development organization owned by the RBOCs. Bellcore represents the RBOCs in
developing standards for Telco equipment and in testing equipment compliance to
those standards. Bellcore also offers educational and training programs open to all
interested parties.
BLF (See Busy Lamp Field)
Standard Telephony Features Glossary
__________________________________________

4 World Wide Training Standard Telephony Features - 10/7/01 3:46 PM
Blockage is a percentage of calls that do not complete due to lack of resources such as
an incoming call to a PBX that cannot be completed because there are no trunk
circuits available to transport the call to the PBX or the percentage of devices that will
not get service when simultaneous resources requests exceed system resource (such as

time slots or tone senders) availability. (See Traffic and Erlang)
Blocking/Non-Blocking are terms used to describe the ability to provide resources to
all configured devices simultaneously. A Non-Blocking switch can provide a time-slot
or transmission path to all devices simultaneously. A Blocking system cannot. Most
PBX systems are Blocking in their standard configuration but with additional
resources or specific methods of allocating ports many of them can achieve a Non-
Blocking state. This is usually an expensive proposition and may be a competitive
advantage for true non-blocking systems.
Bridged Call Appearance allows single-line and multi appearance telephone users to
have an appearance of another user’s primary extension number. The bridged call
appearance can be used to originate, answer, and bridge onto calls to or from the other
user’s primary extension number.
Busy Lamp Field is an indicator that a station is in use. (See also DSS) In some
systems this is a physical or software module that attaches to a phone, Attendant
Console or softphone and can be used to monitor several or hundreds of
extensions/directory numbers for state. Some examples of ‘state’ may be:
1. in use or busy
2. not-in-service or in do-not-disturb condition
3. available or idle
Busy Override – allows approved subscribers to override/interrupt a busy station.
Broken dial tone is an interruption of the dial tone. In North America dial tone is
generally a steady tone so that a broken dial tone may be used to indicate a message
waiting on a device or line. This may be supplementary to a message-waiting
indicator such as an LED or display symbol or it may be used on a device incapable of
displaying a visual message-waiting indicator. (See also Stutter Tone)
Bypass is equipment or circuits that allows incoming trunk circuits to be bridged
directly to specific telephones in the event of a catastrophic system failure. Some
PBXs had an optional Bypass capability that could be added directly to the system
while others used 3
rd

party equipment to provide the same capability. Analog Bypass
is the most common type but there are Bypass units that can cross-connect/bridge
incoming T1/Analog circuits to digital/analog phones.
Buzz – Manager/Secretary feature that lets the manager to buzz the secretary to come
into the office or the Secretary can buzz the Manager alert them to a call or visitor.

Standard Telephony Features Glossary
__________________________________________

5 World Wide Training Standard Telephony Features - 10/7/01 3:46 PM
C
Call Blocking is controlled through the end-users class of service. If the end-user has
not been given access to a specific trunk group or trunk the call will be blocked.
Call Coverage provides automatic redirection of calls to alternate answering
positions in a Call Coverage path. Call Coverage allows you to:
1. Establish coverage paths with alternate answering positions
2. Establish redirection criteria that govern when a call redirects
3. Redirect calls to a local switch location
4. Redirect calls to a location on another switch
5. Redirect calls to a remote location
6. Redirect calls based on time-of-day
This allows users to change back and forth between two coverage choices (either
specific lead coverage paths or time-of-day tables). Users may make these changes
either an on- or off-site location.
Call Detail Recording CDR collects detailed information about all incoming and
outgoing calls on specified trunk groups and, if you use intraswitch call detail records,
about calls between designated extensions on the switch. It sends this information to a
printer or other call detail records output device that may also provide reports. You
can use this information to compute call costs, allocate charges, analyze calling
patterns, detect unauthorized calls, and keep track of unnecessary calls. (See also

SMDR)
Call Duration is the period of time that begins with Answer Supervision (destination
off hook) and ends when the call is terminated.
Call Forwarding allows users to redirect calls to designated destinations. The
forwarded-to destination can be an internal extension, external (off-net) number, an
attendant group, or a specific attendant. Call Forwarding provides five functions:
Call Forwarding-All Calls, Ring-no-answer, Busy — Allows a user to redirect
incoming call to the forwarded-to destination.
Call Forward Busy/Don’t Answer — Allows a user to redirect incoming calls to a
forwarded-to destination only when the user is busy or when the call is not answered
after an administrable interval. If the extension is busy, the call forwards
immediately. If the extension is not busy, the incoming call rings the called extension,
then forwards only if it remains unanswered longer than the administered interval.
Call Forwarding Off Net/External — Allows a user to forward calls to an off-net
destination.
When Coverage of Calls Redirected Off-Net is activated, calls can be monitored for
call progress tones, and if a call is not answered, it is returned to the switch for call
coverage processing in some circumstances.
Standard Telephony Features Glossary
__________________________________________

6 World Wide Training Standard Telephony Features - 10/7/01 3:46 PM
Call Forwarding Override allows the user at the forwarded-to extension to override
Call Forwarding at the forwarded-from extension on a per-call basis so the user can
initiate a call or transfer a call back to the forwarded-from extension.
Call Hold allows telephone users to disconnect from a call temporarily, use the
telephone for other call purposes, and then return to the original call.
Called Party Address This is the destination phone number of a call delivered to a switch.
For instance this could be the CLID (Calling Line ID) of a call delivered to a PBX using DID
or two-way trunks. (See also DID)

Calling-party-ID Interface to the PSTN is provided through a digital gateway
supporting ISDN Primary Rate Interface. The digital gateway must support ISDN
Primary Rate Interface from the network to receive this feature. On an inbound call
the network passes the telephone number to the gateway. The gateway then passes the
information to the IP telephony server where the information is passed on to the
telephone instruments and reports such as call detail records.
Call Park allows users to put a call on hold in an ‘orbit’ (an orbit is something like a
phantom extension) and then retrieve the call from any other voice terminal within the
system by dialing the orbit number. This is commonly used in an
Attendant/Subscriber scenario.
On some systems the call was actually parked on a idle/busy extension. If it was
parked to a busy extension the busy subscriber would hear an audible beep tone
indicating a call had been parked on their extension. The party they were talking to
would not hear the beep. This feature is commonly used in a Boss/Secretary scenario.
In each scenario if the call is not picked up in a reasonable time the call should ring
back to the attendant or the party that placed the call in park. With the advent of
voicemail the Call Park feature is not as commonly used.
Call Pickup allows a user to answer calls that alert at other extension numbers within
the user’s specified call pickup group.
Call Pickup – Directed allows subscriber to press a key/ dial a code and then an
extension number to pickup a ringing call at a specific station
Call Pickup – Group allows user to enter a code and pickup any ringing phone
configured in the same group
Call Quality is a measure of the expected quality as determined by the MOS of the
Codec (with or without voice activity detection), and the delay, jitter, and congestion
on the network.
Call Waiting/ Retrieve allows a call to overflow to a second line on an end-users
telephone. When the call arrives the end-user will have both a visual and audible
notification. The end-user places the first caller on hold and depresses the second line

to retrieve the call.
Calling Party Name Display feature provides internal station users with an enhanced
visual aid in making and receiving calls. In addition to the calling or called party’s
Standard Telephony Features Glossary
__________________________________________

7 World Wide Training Standard Telephony Features - 10/7/01 3:46 PM
extension number, a customer-definable identification (typically the party’s name)
also appears on a stations LCD display.
Calling Party Number Display feature provides internal station users with a visual
display of the internal and external numbers terminating to their station set. The
external number appears only when the local provider passes the information through
the PSTN network.
Camp On feature allows callers to wait for a busy station or trunk to become
available. Typically caller will hear a tone identified as camp-on. May require caller
to stay in off-hook condition or may support automatic callback. Some systems
support this from both internal and external callers. System may require input of an
access code when reaching a busy station or be set to automatically camp-on. Some
phone systems will not allow camp-on to phones with voicemail configured as the
forwarding target.
CAS Centralized Attendant Service – allows a centralized group of attendants to
answer calls across the network and transfer them back to stations without holding up
the private network links. (Sometimes call release-link trunks)
CCITT - Consultant Committee on International Telephone and Telegraph
An international organization that develops standards and defines interfaces for
telecommunications. (Now known as ITU International Telecommunications Union).
CCS is an Acronym that may identify different functions:

1. Common Channel Signaling (out of band signaling such as occurs with
ISDN) Many PBXs proprietary private network link either use an actual PRI

interface or simulate a D-channel on standard DS-1 circuits.
2. Centum (Roman Numeral C = One Hundred) Call Seconds - standard unit of
traffic, used in communications engineering. Typically the CCS associated
with common station traffic is 7 to 12 CCS. This number is an assumption
when calculating traffic when the actual traffic per station is unknown. (See
also Erlang)
Cell can be identified by a couple of definitions:

1. Packet switching information grouped in units of uniform size. Cells are
fixed-length packets. (e.g. ATM 53-byte cells)

2. A small group acting as a unit in a larger organization (e.g. one of the separate
geographical areas covered by a radio transceiver antenna in a multi-antenna
cellular phone system, a spreadsheet cell, a biological cell, etc.).
Central Office is a location that houses a telephone system generally used for Public
Network interfaces such as links between Central Offices, Business Circuits (Trunks)
and home telephone lines. Provides phone service to subscribers within a specific
geographical area.
Central Processing Unit is the part of the switch containing the logic, computation
and control circuits.
Standard Telephony Features Glossary
__________________________________________

8 World Wide Training Standard Telephony Features - 10/7/01 3:46 PM
Centrex – public CO offering that provides business telephone services similar to a
PBX. Subscribers can dial by directory number, have voicemail and other business
features/applications in a limited fashion compared to a PBX. Usually managed by the
LEC and includes long term contracts.
Centrex Flash – allows subscriber to issue a command that will in turn cause a flash
to be sent to the Centrex system to perform transfers and other features.

Channel or Time Slot is a single, bi-directional, direct connection between two TDM
devices. An actual path you can talk or send data over.
Circuit is a physical path through which electrical signals can pass. It consists of a network of
conductors and other components, separated by insulators. Technically this term cannot be
applied to fiber optic or other "non-metallic" paths.
Circuit Switching A system where a dedicated channel is allocated to the users of that call
for the duration of that call. That channel is allocated for the duration of the call regardless if
information is being transmitted at any given moment. Bandwidth through the channel is fixed,
at no time may this bandwidth be exceeded. If this bandwidth is not used it is wasted. While
inherently inefficient, the dependable and reliable nature of circuit switching makes it ideally
suited to real-time voice and audio/video conferencing applications. This is in stark contrast to
systems where statistical multiplexing is used. (See Statistical Multiplexing)
Class 3 - IEC - Interexchange Carrier
Hierarchical interconnection for Class 4 and optional Class 5 Switches

Class 4 - Tandem Office - Toll Office
Interconnection for Class 5 Switches and long distance via Class 3 IECs. Optional
direct connection to higher volume Class 4 sites. A Class 4 may also serve as a Class
5 CO.

Class 5 - Central Office -End Office
Connection to local Customer Premise Equipment and local switching. Capacity
typically is up to 100,000 lines, 1 to 10 NXX.

Class of Service - COS
In some PBX systems the COS is used to group telephones and resources, control
access to facilities and provide limitations on what numbers can or cannot be called. It
can also be used to control access features that can or cannot be accessed. For
example; An Executive telephone with COS 10 might be allowed to call long distance
without entering an account code but a lobby phone with COS 3 might be required to

enter an account code even to dial local numbers. Any other phones assigned COS 10
would have the same restrictions and limitations as the Executive telephone. COS
could also be used to perform call blocking so that if blocking was setup between
COS 3 to COS 10 then any phones assigned to COS 3 could not call phones/trunks
with COS 10 but COS 10 could still call COS 3. This is an example of a patient room
phone (COS 3) being blocked from calling the Doctor’s phone (COS 10) but the
Doctor could still call the patient room. In Cisco Call Manager system these functions
can be performed with Partitions and Calling Search Space.
CLEC Competitive Local Exchange Carrier. This is your local telephone service
provider who is one of the new-generation providers rather than a RBOC or
Standard Telephony Features Glossary
__________________________________________

9 World Wide Training Standard Telephony Features - 10/7/01 3:46 PM
Independent. A CLEC is really just an Independent albeit one formed after the
divestiture of AT&T. (See LEC)
CLID Calling Line Identification. This is the ISDN and SS7 equivalent of Caller
ID; I.E. the number of the calling party. (See also ANI)
CO Central Office. The Telco facility where your local telephone circuit leads to.
Contains Switches and Trunks as well as the local telephone circuits.
CPE Customer Premise Equipment- Customer owned equipment located at his/her
facility. In the USA and Canada the NT1 is part of the CPE
Conference – allows 3 or more callers to join in a single conversation
Conference Add/Drop – add or remove callers from conference
cRTP -Compressed RTP or RTP Header Compression, is a method for making the
VoIP packet headers smaller to regain some of the "lost" bandwidth. cRTP takes the
40-byte IP/UDP/RTP header on a VoIP packet and compresses it to 2-4 bytes per
packet, yielding approximately 11.2K of bandwidth for a G.729 encoded call with
cRTP. (See RTP)
CSU/DSU is a device that incorporates the functions of a CSU (Channel Service Unit)

and a DSU (Data Service Unit). This device is typically a CPE device used to separate
the customer environment from the carrier environment. Various CSU/DSU units
have the ability to support different line code formats, reports, troubleshooting tools
and features.
CODEC is a term combining COder and DECoder. The coder portion receives
analog signals such as a speakers voice and converts it into a digital representation of
the analog signal for example PCM. At the receiver side the decoder portion translates
the digital signal back into an analog voice signal for the end user. CODEC can also
be used to perform compression.
Com Group – includes a group of stations that can override features such as do-not-
disturb by dialing a com group index number.
Computer Telephony Integration - CTI
The integration of telephony function with computer applications.
Conference is a single connection combining more than 2 parties into a conversation.
Most PBX systems state a maximum number of parties and further qualify it with how
many can be external to the system. PBX manufacturers usually set a limit to the total
number of attendees and simultaneous conferences. Some PBX manufacturers offer
an optional enhanced conference bridge capability by adding conferencing cards or
adjunct systems to provide for increased capacity of both attendees and simultaneous
conferences.
Conference Bridge (or MCU) is a device that is used to blend the audio signal from
more than 2 callers into a single conversation.
Country Code
Two or three digit codes used for International calls outside of the North American
Numbering Plan area codes. Dial: 011 + country code + city code + local phone
number) (e.g. "011 + 91 + 22 + 123- 4567" 91 = India, 22 = Bombay)
Standard Telephony Features Glossary
__________________________________________

10 World Wide Training Standard Telephony Features - 10/7/01 3:46 PM

CSU/DSU is a device that incorporates the functions of a CSU (Channel Service Unit)
and a DSU (Data Service Unit). This device is typically a CPE device used to separate
the customer environment from the carrier environment. Various CSU/DSU units
have the ability to support different line code formats, reports, troubleshooting tools
and features.


D

D-4 (or Super Frame SF)
A data transmission format comprised of 12 frames of 192 bits each. A single 193rd
bit is used for link control and error checking. As an industry standard, D4, also
known as SF, has been superseded by the Extended Super Frame (ESF) format.
However because ESF is not backward compatible and there continues to be a large
installed base of channel banks and DS-1 Multiplexers that are based upon D4, it is
still the default private line formatting technique.
D-4 Channel Bank
A multiplexer used to convert 24 voice grade analog or data channels into a DS-1.
The D-4 is not equipped for software-controlled provisioning or remote circuit testing
DACS - Digital Access Cross-Connect System is a digital switching facility
interconnection device. A DACS allows reconfiguration of lower levels of capacity
within a circuit without the need for manual changes in the interconnections. A DACS
is similar to a MUX, but a DACS permits software changes that would require
physical changes with a MUX.
D Channel - Data Channel or Delta Channel (depending on who you ask). The
channel that handles ISDN network related data between the user's equipment and the
Telco switch. Used to carry data to set up calls and receive calls. Some Telco's also
allow users to use the D channel to access the packet data network, with appropriate
terminal equipment.

Dialed Number Identification Service – DNIS is an optional feature. DNIS delivers
identifying digits (up to 14 digits) that distinguish incoming calls. This allows CPE to
identify which number was dialed when multiple numbers terminate on the same
trunk group and offers the ability to route calls based on the dialed number. (See also
ANI)
Decibel - Db - db
A unit of power (sound, electrical or optical) increase (amplification) or loss
(attenuation) that is proportional to the exponential increase or decrease in power.
Standard Telephony Features Glossary
__________________________________________

11 World Wide Training Standard Telephony Features - 10/7/01 3:46 PM
Demarcation Point - Demarc
A point (such as a jack or cross-connect panel) at which ownership or responsibility
for operating and maintaining facilities passes from one party to another.
Dial Tone
Start Dial/Ready To Place/Originate A Call. When the off hook indication is received
at a central office, a dial tone signal is sent to the originating caller on a switched
network to indicate that the switch is ready to accept a number.
DID Intercept accommodates an FCC requirement that calls to non-working DIDs or
unused DIDs within a purchased block be routed to a recorded announcement
notifying the caller they have read a non-working DID. Generally this was preferred
since it did not provide answer-supervision. An alternative to the recorder was routing
the caller to a human although in most systems that would provide answer-
supervision and begin the billing process. Voicemail was not considered a suitable
recorder interface since it generally provides answer-supervision as soon as it
connects.
Digital
A device or method that uses discrete variations in voltage, frequency, amplitude,
location, etc. to encode, process, or carry binary (zero or one) signals for sound,

video, computer data or other information. For example, a digital clock displays the
time as discrete numeric values, rather than angular displacement of analog hands.
Digital communications technology generally permits higher speeds of transmission
with a lower error rate than can be achieved with analog technology. When analog
signals are received and amplified at each repeater station, any noise is also amplified.
A digital signal, however, is detected and regenerated (not amplified). Unlike
amplification, any noise (less than a valid signal) is eliminated by digital regeneration.
Digital European Cordless Telecommunications
A wireless standard for communications, operating at 1,88-1,9 GHz. The system is
developed for high traffic rates and small cells. Applications are private, residential
and business telephone and data transmissions.

Digital Phones sometimes called Feature Sets are usually proprietary devices built by
the PBX manufacturer or built to their proprietary specifications. Typically connected
to cards in the PBX specifically designed to interface to these phones. Digital phones
are generally much more expensive (and feature rich) than analog phones. Some
manufactures require cards and phones both to be upgraded or changed when
expanding system capacity or enhancing software. Digital phones usually had some
number of line/feature keys. If the phone has more than one line it is called a “multi-
line” set. Some phones have displays, speakers, interface(s) for special adapters (such
as data ports, BRI or analog extenders), DSS/BLF modules and key expansion
modules. In addition some manufacturers require specific Digital Phones to be used
for certain functions such as ACD. If a non-ACD designated set is used the
manufacturer will provide little or no support for the customer. Many manufacturers
proprietary voicemail system will use the digital ports to integrate to the system. Since
this is a proprietary interface it makes it very difficult for competitive equipment to
attain a comparable level of integration.
Standard Telephony Features Glossary
__________________________________________

12 World Wide Training Standard Telephony Features - 10/7/01 3:46 PM
Direct Inward Dialing (DID) trunk group allows an incoming call from the exchange
network to reach a specific extension number directly without attendant intervention.
In North America DID blocks are purchased in groups of 10, 20, 100 or larger.
Direct Inward System Access - DISA is the ability to access a PBX from an outside
telephone number. For example, a caller might dial an assigned number, input a
security code and then use the PBX to place a long distance call.
Direct outward dial trunk group allows the station end-user to call outbound by
dialing an access code or by depressing a pre-defined feature key with the trunk
appearance on it. The class of service assigned to their station determines the end-
users outbound dialing privileges. The class of service may be temporarily upgraded
by use of an authorization code.
Direct Page – allows paging directly through a station’s speakerphone.
Direct Trunk Select – lets a technician bypass routing tables to test specific trunks or
circuits.
DISA – (See Direct Inward System Access)
Distribution Group - distributes calls more evenly than standard hunt groups. If the
first call goes to station A the next call will go to station B even if A is available.
Disconnect - Call termination and the information associated with it such as time of
day, who disconnected (originator, destination, etc.)
Distinctive Ringing provides several ringing cycles to help telephone users and
attendants distinguish between incoming call types.
DN Directory Number is a phone number used within the PBX. Length may
typically be anywhere from 2 to 10 digits with 3 or 4 digits as the most common.
DNIS (See Dialed Number Identification Service)
Do Not Disturb allows guests, attendants, and authorized front-desk telephone users
request that no calls, other than priority calls, terminate at a particular extension until
a specified time. At the specified time, the system automatically deactivates the
feature and allows calls to terminate normally at the extension.
Drop/Insert (Add/Drop) is the ability to separate portions of a DS-1 so that it can

transport different types of information or terminate different traffic types on a single
transport medium. For example an Add/Drop CSU might be used to share a T1 for
both voice and data. If a voice application requires 10 channels and the remainder
might be used to transport data. This is most commonly used between sites on a Point-
to-Point T1/E1 but could also be used with an ISP/Carrier to transport both PCM
phone calls and data to the cloud where the voice would be carried by the PSTN and
the data would be redirected to the ISP service.
DS-0 Digital Signal, level 0 is 64 kilobits. It is equal to one voice
conversation/channel digitized under PCM (See DS-1 also)
DS-1 Digital Signal level 1 is 1544 kilobits (1.544 megabits), which is twenty-four
64k, channels plus framing bits (24 x 64,000 = 1536000 bits/sec + 8000 frame bits
=1544000 bits or 1536kb or 1.544mb)
Standard Telephony Features Glossary
__________________________________________

13 World Wide Training Standard Telephony Features - 10/7/01 3:46 PM
DSS Direct Station Select is similar in function to BLF (see Busy Lamp Field)
DTMF, Dual-Tone Multi-Frequency, is the ITU and Bellcore signaling standard for
telephone handset push-button keypads. The keypad is a 4x4 matrix of frequencies
each button corresponding to two frequencies. Not only has DTMF become important
for rapid dialing, but has also taken on an added dimension of providing voice mail as
well as other menu driven options during connected calls. DTMF specifications are:
Each digit corresponds to 2 frequencies:
• Dynamic Range - 25 dB
• Twist - 8 dB
• SNR - 30 dB
• Minimum Recognition - 40 msec
• Maximum Rejection - 27 msec
• False Alarm - 0 (30 min Mitel Test Tape)
Digit

Row
Frequency
(Hertz)
Column
Frequency
(Hertz)
Return

Code
1 697 1209 0x10
2 697 1336 0x11
3 697 1477 0x12
A 697 1633 0x1C
4 770 1209 0x13
5 770 1336 0x14
6 770 1477 0x16
B 770 1633 0x1D
7 852 1209 0x16
8 852 1336 0x17
9 852 1477 0x18
C 852 1633 0x1E
* 941 1209 0x19
0 941 1336 0x1A
Standard Telephony Features Glossary
__________________________________________

14 World Wide Training Standard Telephony Features - 10/7/01 3:46 PM
# 941 1477 0x1B
D 941 1633 0x1F

E
E1 is the European digital transport medium equivalent to North American T1. E1
carries information at the rate of 2.048 million bits as opposed to T1 at 1544 million
bits per second. E1 uses 30 channels for carrying voice or data and 2 channels for
signaling and control. A common term used to describe E1 is “30+2”. When used as
the underlying media for ISDN PRI, one of the control and signaling channels is used
as the D channel while the 30 voice and data channels are used for B-channels.
E-9-1-1 – Enhanced 911
Echo Cancellation
A technique used with voice circuits to isolate and filter unwanted signal energy that
accompanies analog transmissions.

Echo Canceller
A circuit feature that turns off the incoming signal while one end of the call is talking
(to avoid an annoying long distance echo). It must be disabled for Full Duplex
(simultaneous 2-way calls). An echo canceller does not turn off the voice channel, as
stated, but electronically removes unwanted echo, while maintaining a full-duplex
channel. An echo suppressor disables the channel in one direction or the other,
depending on who is talking. Echo cancellers must be disabled for some types of
high-speed modems calls, and must also be disabled for "clear channel" data calls,
such as ISDN.
Erlang - Traffic Unit - (1 Erlang = 3600 Calling Seconds = 36 CCS)
An international unit of average traffic on a facility during a period of time (usually a
busy hour). The number of erlangs is the ratio of the time the facility is occupied
(continuously or cumulatively) to the time the facility is available.

Error-free Seconds
A measure of the quality of the signal being transmitted. It is a percentage

representing the total amount of time over a 24-hour period that the signal contained
bit errors and it is calculated using a test pattern defined in CCITT Recommendation
0.151.
ESF - Extended Super Frame
An enhanced version of D4 formatting, and it is the current industry standard. ESF is
composed of 24 frames of 192 bits each. ESF provides 16 signaling states in the 193rd
bit to ensure synchronization, supervisory control, and maintenance capabilities.
Standard Telephony Features Glossary
__________________________________________

15 World Wide Training Standard Telephony Features - 10/7/01 3:46 PM
Executive Busy Override allows a user to enter into an established connection. A
warning tone notifies the talking parties that a third party is about to enter the
conversation. The executive override feature can be issued after a user has dialed a
busy extension. This feature requires a special class of service.
F
Facility – is commonly used in the PBX environment to refer trunks but can be a
generic term for a logical component of a system (such as a telecommunications
channel, a switch, a computer, groups, a control center, a building, etc.)
Facility Busy Indication provides multi appearance telephone users with a visual
indication of the busy or idle status of one of the following system resources:
1. An extension number
2. A trunk group
3. A terminating extension group
4. A hunt group
5. Any loudspeaker paging zone, including all zones
The Facility Busy Indication button provides the attendant or user with direct access
to the extension number, trunk group, or paging zone. You can store extension
numbers, trunk group access codes, and Loudspeaker Paging access codes in a
Facility Busy Indication button.

FCC - Federal Communications Commission
US regulatory body that regulates interstate communications: licenses, rates, tariffs,
standards, limitations, etc. Appointed by U.S. President.
Feature Access Codes are combinations of signals and DTMF tones invoked by a
user to perform features such as conference, transfer, pickup, park and so on. (See
Analog Phones, Digital Phones and Flash)
Flash is a term describing a signal sent to the PBX indicating that the subscriber
wishes to perform a feature. Originally pressing the hook-switch button(s) on an
analog phone performed a flash by temporarily opening the circuit and interrupting
the current flow. (Note: in some countries Flash is called Ground Flash because the
signal is temporarily taken to ground instead of opening the circuit). Parameters
within the Telephone System identified the length of time required to recognize the
interruption as a flash. If the hook-switch wasn’t held long enough (low-flash
parameter) the system ignored interruption. If the hook-switch were held too long
(high-flash parameter) the call would be disconnected since the system recognized it
as an On Hook signal. Newer analog phones and some digital phones had buttons that
would automatically send a flash signal. In some cases the Low and High Flash
System Parameters would need to be adjusted to accommodate the hard-coded flash
sent by the phone.
Foreign Exchange (FX)
A DS-0 line utilizes Feature Group A facilities on one end of the circuit. The Feature
Standard Telephony Features Glossary
__________________________________________

16 World Wide Training Standard Telephony Features - 10/7/01 3:46 PM
Group A service connects a customer premise in the foreign location with the line side
of a BOC central office switch in the U.S. The customer premise end of the circuit is
referred to as the closed end because it terminates on a station instrument, key system,
or PBX. The CO switch end of the circuit is referred to as the open-end because it is
open to the public switched network. The open end of the circuit appears as a local

business line in a local exchange, different from (foreign to) the local exchange of the
closed end of the circuit. A dial tone from the distant city's local office is heard when
this line is accessed, and a local phone number can be associated with the FX. An FX
has fixed monthly charges for the originating local access, IXC, international circuits.
Usage charges are applied through the local telephone company at the open (US) end.
The advantages of an FX line are the use of a local phone number for long distance
calls and high volume centralized long distance calling at reduced fixed costs. In the
case of international FX services, the open end must be in the US, unless the foreign
PTT can support this service. In many countries this service falls under regulatory
laws.
Fractional T1 - FT1
A service that uses a portion of a 24-channel T1 circuit. FT1 allows 64 Kbps
increments from 2-channel 128 Kbps through all 24 channels at 1.544 Mbps.
Frame Slip (Also called just "slip")
Any shift of the timing on a circuit. Usually the difference between D4 Super Frame
and Extended Super Frame or an un-framed signal stream. During an out-of-frame
condition, one frame slip would increment.
FX (See Foreign Exchange)
FXO Foreign Exchange Office – Usually used to connect loop-start analog Central
Office trunks.
FXS Foreign Exchange Subscriber - Usually used to connect end-user devices such
as telephones, modems, fax machines and so on…

G
Glare - On a POTS line an incoming call is signaled by periodically applying an AC
ring voltage to the line. Since there is a semi random period before the ring, and
pauses between rings, it is possible to seize a line which is "about to ring" (and answer
a call) when attempting to place an outgoing call. When this scenario happens it is
called glare. Glare is much less likely if Ground Start trunks are used. (See Ground
Start Trunk)

GMT
Greenwich (England) Mean Time - Zulu Time GMT is 6 hours later than Central
Standard Time (CST in the northern hemisphere Winter) and 5 hours later than
Central Daylight-Savings Time (CDT in the northern hemisphere Summer). GMT
(Zulu Time) is always the same worldwide. Communication network switches are
typically coordinated on GMT.
Standard Telephony Features Glossary
__________________________________________

17 World Wide Training Standard Telephony Features - 10/7/01 3:46 PM
Grade Of Service - This is simply the ratio of calls blocked to total calls in a decimal
form. So a grade of service of P.08 would represent 8% blocking. Telephone tariffs
regulate the acceptable average grade of service that must be provided on public
networks.
Ground Start Trunk – Is a type of telephone trunk where the request to make an
outgoing call (i.e. request for dial tone) is made by briefly grounding the Tip
conductor. Many PBX systems use ground start trunks as they are less prone to glare
than Loop start trunks.(See Loop Start Trunk and Glare)

H

H.323 This is an umbrella recommendation from the International
Telecommunications Union (ITU). It is part of a family of ITU–T recommendations
(H.32x) that provides multimedia communication services over a variety of networks.
It sets standards for multimedia communications over LANs that do not provide a
guaranteed Quality of Service (QoS) and provides a foundation for audio, video, and
data communications across IP-based networks, including the Internet. H.323 offers
interoperability of multimedia products and applications from multiple vendors. RTP
is the media protocol used for H.323.
The ITU has ratified the following core H.323 components

• H.225: Specifies messages for call control including signaling, registration and
admissions, and packetization/synchronization of media streams. Includes H.245
initiation information.
• H.245: Specifies messages for opening and closing channels for media streams,
and other commands, requests and indications
• H.261: Video codec for audiovisual services at P x 64 Kbps
• H.263: Specifies a new video codec for video POTS
• G.711: Audio codec, 3.1 KHz at 48, 56, and 64 Kbps (normal telephony)
• G.722: Audio Codec, 7 KHz at 48, 56, and 64 Kbps
• G.728: Audio Codec, 3.1 KHz at 16 Kbps
• G.723: Audio Codec, for 5.3 and 6.3 Kbps modes
• G.729: Audio Codec

Handsfree – allows the subscriber to answer the phone without lifting the handset…
Some systems require that the called party press the speakerphone button.
Standard Telephony Features Glossary
__________________________________________

18 World Wide Training Standard Telephony Features - 10/7/01 3:46 PM
HDB3 - High Density Bipolar Three
A line interface standard for E1 which is similar to B8ZS, which eliminates data
streams with 8 or more consecutive zeros. Allows for 64Kbps clear channel capacity
and still assures a minimum ones density required by E1 lines. It is an E1 line coding
method. This is the more modern line coding method of the two commonly available. . See
also AMI and B8ZS.
Holding Time
The total time from you picking up the handset, to dialing a number, to waiting for it
an answer, having a conversation on the line, to hanging up and replacing the handset
in its cradle. You are never billed for holding time. You are always billed for only
conversation time that is only part of the holding time. Although, holding time figures

are nice to know when you are trying to determine how many circuits you need. You
will need sufficient circuits to support dialing, etc. - even though you're not being
billed for that time.

Hoot-n-Holler - also known as a shout down
A voice only full time circuit that connects a speakerphone in one location to a
speakerphone in a distant location. This type of circuit is normally open at all times to
allow two-way communications without having to pick up the receiver or dial the
phone. Speakerphones used in this type of circuit are full duplex, transmit and receive
units. This circuit is very similar to the ARD and MRD and is also used by the
financial industry.

Hold allows telephone users to disconnect from a call temporarily, use the telephone
for other call purposes, and then return to the original call.
Hot Line allows designated station sets to place calls to a predetermined destination
simply by going off-hook. The destination may be internal or external to the system
and the call does not require attendant intervention.
Hunt Group - A group of telephone channels configured so that if the first is busy
(engaged) the call goes to the next channel, if that channel is busy it goes to the next
channel, etc. Hunt groups may hunt from the highest to the lowest, the lowest to the
highest, or on some other arbitrary pattern. But the order of hunting will usually be
fixed, beginning with one channel and working through ("hunting") until an unused
channel is found. The term may have originated back in the old manual switchboard
days when the operator literally hunted for an unused jack to plug a cord into. This
arrangement is very common in business scenarios where a single incoming number is
given to the public, but multiple incoming channels are supported.
Hybrid Key System
A CPE system that has characteristics of both a key system and a PBX system.

I

Standard Telephony Features Glossary
__________________________________________

19 World Wide Training Standard Telephony Features - 10/7/01 3:46 PM
IDF – Intermediate Distribution Frame – The IDF is commonly used to terminate
bulk cables from the MDF and provide a distribution point for subscriber stations.
(See MDF)
IEC- InterExchange Carrier. "Long Distance" carrier. Handles Interlata and
interstate calls. Also referred to as IXC.
ILEC - Incumbent Local Exchange Carrier. A local Exchange Carrier that entered
the marketplace before the enactment of the 1996 Telecom act
IMUX Inverse Multiplexing - A method of combining and later separating 2 data
streams that does not involve the telephone network. Inverse multiplexing is the most
common way of achieving this function in Codecs operating at 128kbps or less over
ISDN
In Band Signaling-A signaling system where network information such as address
and routing information are handled over the communications (voice) path itself.
Usually the information is represented in the form of tones, however DC loop current
signaling also qualifies as In Band Signaling
Incoming Call Display allows the system to provide information about an incoming
call when the called party is active on a call. The system does this by displaying
incoming call information on the called party’s display-equipped telephone.
Interactive voice response A device using remote touch-tone telephones with a
digitized, synthesized voice that reads information on a computer screen to the distant
caller. When someone dials in, the interactive voice response unit responds with a
prompt to get a personal identification number (PIN), and so on. The interactive voice
response unit provides employees and customers 24-hour access to information (i.e.
employees’ records, customer billing information) without human intervention.
Independent- Any of the phone companies in existence at the time of divestiture that
were not affiliated with the Bell System

Information Digits
CDR call type options. Two digit codes which precede the 7-or-10-digit destination
number and inform exchange carriers and IECs about the type of line that originated
the call, any special characteristics of the billing number, or certain service classes.
These codes plus the destination number are part of the signaling protocol of equal
access offices. Bellcore defines these codes. Examples: 00 - POTS, 01 - Multiparty,
02 - ANI Failure, 06 - Hotel/Motel, 07 - Special Operator Handling, 20 - AIOD, 24 -
800, 27 - Coin, 30 - Unassigned DN, 31- Trouble/Busy, 32 - Recent change or
disconnect, 34 - Telco Operator, 52 - Outward WATS, 61- Cellular 1, 62 - Cellular 2,
63 - Roaming, 70 - Private Pay Phone, 93 - Private virtual Network

International Telecommunication Union (ITU) was formerly known as CCITT.
(See CCITT and ITU-T)
IP Internet Protocol. This network layer protocol in the TCP/IP stack offers a
connectionless internetwork service. It provides features for addressing, type-of-
service specification, fragmentation and reassembly, and security.
Standard Telephony Features Glossary
__________________________________________

20 World Wide Training Standard Telephony Features - 10/7/01 3:46 PM
IP Precedence IP Precedence utilizes the three precedence bits in the IPv4 header's
Type of Service (ToS) field to specify class of service for each packet. You can
partition traffic in up to six classes of service using IP Precedence. Within a Cisco
voice environment voice packets are generally given IP Precedence 5 while data
packets are generally given IP Precedence 2.

IP Precedence Values

Number

Name
0 routine
1 priority
2 immediate
3 flash
4 flash-override

5 critical
6 internet
7 network

ISDN - Integrated Services Digital Network- A relatively new and highly flexible
type of telephone service which allows dialing on digital lines with multiple bi-
directional "Bearer” channels each with a capacity of 56 or 64 Kbps and a single bi-
directional "D-channel". (See BRI and PRI)
ISO - International Standards Organization
Defines communications and computing standards. ISO 7776 - High-Level Data Link
Control Procedures X.25.
Intercept Handling –Intercept Handling lets the system control what happens to a
call when the call cannot be completed to the required destination. A call may be
routed to a tone or to a directory number. Two alternate destinations may be
programmed for each condition.
ITU Telecommunication Standardization Sector (ITU-T) is one of the three
Sectors of the International Telecommunication Union (ITU). It was created on 1
March 1993, replacing the former International Telegraph and Telephone
Consultative Committee (CCITT) whose origins go back to 1865.
J
Standard Telephony Features Glossary
__________________________________________

21 World Wide Training Standard Telephony Features - 10/7/01 3:46 PM
JTAPI - Java Telephony Applications Program Interface. This portable, object-
oriented application programming interface for Java-based computer-telephony
applications supports both first- and third-party telephony application domains. It
brings simplicity to the most basic telephony applications and provides a scalable
framework that spans desktop applications to distributed call center telephony
applications.

JTAPI interfaces applications directly to service providers or acts as a Java interface
to existing telephony APIs, such as SunXTL, TSAPI, and TAPI. It is based on a
simple core that is augmented with standard extension packages. It runs on a wide
range of hardware configurations wherever Java run-time can be used.

K
Key Telephone System - A system that allows multiple telephones to share multiple
pre-determined telephone lines. The system provides indicators to allow the users to
understand the status of each line available on a given phone. It is up to the user to
provide the intelligence to select an unused line, or answer a ringing line, for example.
See also PBX.

L
Last Number Redial allows a user to automatically redial the last number dialed.
The system saves the digits of the last number dialed, whether the call was dialed
manually or with abbreviated dialing. When users press the Last Number Redial
button the system places the call again.
LATA -Local Access and Transport Area. The area within which calls are routed by
your Local Exchange Carrier (LEC) Under the divestiture of the Bell System calls
going outside of this area must be handled by an Interexchange carrier (IEC). With
the latest round of de-regulation the usual IEC companies are being allowed to
compete in the IntraLATA long distance market and LECs are beginning to be

permitted to handle InterLATA calls
LDAP Lightweight Directory Access Protocol. This is a client-server protocol for
accessing online directory services. It runs directly over TCP and can be used to
access a standalone LDAP directory service or to access a directory service that is
back-ended by X.500
Least Cost Routing LCR – offers different paths to the PSTN based on various
factors associated with the subscriber and the cost of the route.
LEC - Local Exchange Carrier. Your local telephone service provider.
Standard Telephony Features Glossary
__________________________________________

22 World Wide Training Standard Telephony Features - 10/7/01 3:46 PM
Line - An electrical connection between a telephone service provider’s switch (LEC
or CLEC) and a telephone terminal or Key system. An electrical connection between
a telephone service provider’s switch and another switch is called a trunk. Note that
some types of physical lines offer more than one channel.
Line Coding, T1 - The clock signal for T1 is derived at the far end from the data bits
themselves. Therefore T1 lines have certain restrictions as to the data allowed. No
more than 15 zeros shall be sent in a row; and average density of 12.5% ones must be
maintained. The CSU is responsible to ensure that these requirements are met. The
line encoding method, AMI or B8ZS determines exactly how these requirements are
met while still allowing recovery of the original data at the far end. Your Telco will
determine the method used on a specific circuit. B8ZS is preferred. E1 circuits have
similar restrictions. HDB3 is preferred for E1 circuits.
Line Format, T1- Modern T1 circuits usually use either Superframe (sometimes
called SF or D4) or Extended Superframe (sometimes called ESF) line formatting.
The type of framing used is determined by your Telco. ESF is preferred.
Line Selection allows a station user the ability to depress a pre-configured line button
to dial a number or to answer an incoming call. You must have added line numbers on
the user's phone for this button to work.

Loop - The telephone circuit from the CO to the customer's premises. Generally
refers to a copper cable circuit.

Loop Start Trunk - A plain old telephone line connected to a PBX switch. The PBX
signals the "off hook" condition by allowing DC current to flow. Ground Start Trunks
are generally preferred for use on PBXs to prevent glare. See Ground Start Trunks.
See also Glare.

Loudspeaker Paging Access allows an access code or codes to be dialed from
a station set. When the access code is dialed the paging system is activated and
the call is broadcast across the loudspeakers. Multiple access codes can be
dialed when more then one paging zone is required.
M
M13
A multiplexer that adapts DS-1 circuits to a DS-3 circuit
Malicious Call Trace allows you to trace malicious calls. Malicious call trace allows
you to define a group of telephone users who can notify others in the group when they
receive a malicious call. These users then can retrieve information related to the call.
Using this information, you can identify the malicious call source or provide
information to personnel at an adjacent switch to complete the trace. Malicious call
trace also allows you to record the malicious call. You allow users in the group to
activate malicious call trace and/or to control malicious call trace. The controlling
Standard Telephony Features Glossary
__________________________________________

23 World Wide Training Standard Telephony Features - 10/7/01 3:46 PM
terminal user, or controller, receives the information that malicious call trace collects
on the call.
MAPI Messaging Application Programming Interface. MAPI is a standardized set
of C functions placed into a code library known as a Dynamic Link Library (DLL). It

was originally designed by Microsoft, but now has the support of third party vendors.
It takes advantage of the Windows messaging subsystem, supported by default with
Microsoft Mail or Microsoft Exchange. With MAPI, any Windows application can
become “mail-enabled.” It is also available to Visual Basic application writers
through a Basic-to-C translation layer.
MDF – Main Distribution Frame – on the customer premise the MDF is generally
located near the PBX and provides termination for station lines or bulk cables from
IDFs that might interface between the stations and the MDF. It is also termination
point for trunk facilities from the CO. The MDF is usually where the cables from the
PBX will terminated and cross-connected to stations and trunks. (See also IDF)
Meet Me Conference. When Meet Me Conference users press a button, they are
initiating a Meet Me conference and they expect other invited users to dial into. Only
the person initiating Meet Me conference needs a Meet Me button.
Message Waiting provides a visual indication that a voice message has been left for
the user. The end user depresses the button and the call is directed to a pre-defined
destination for message waiting.
MGCP Media Gateway Control Protocol. Nortel Networks developed this
proposed control and signal standard. It competes with the older H.323 standard for
the conversion of audio signals carried on telephone circuits (PSTN) to data packets
carried over the Internet or other packet networks. It is a combination of the Internet
Protocol Device Control (IPDC) specification and the Simple Gateway Control
Protocol (SGCP).

MGCP enables external control and management of media gateways and end-points
by software programs known as "call agents" or "media gateway controllers.” Media
gateway devices include voice over IP gateways, voice over ATM gateways, modem
banks, cable modems and set-top boxes, soft PBXs, and circuit cross connects.
Mobility (follow me) allows an IP telephone to be moved to any location throughout
the facility. When the IP telephone is moved to a new location the instrument registers
with the IP Telephony server and the user is allowed the ability to use their IP

telephone again.
Modem - Modulator/Demodulator - End User Computer Interface
Mµ-Law - North American compression standard used in conversion between analog
and digital signals in PCM systems. It is similar to the European a-law encoding.
While primarily used in North America, Japan and a few other countries also use the
Mµ-Law format.
Multiple Line Appearances Per Phone is determined by the number of line
appearances the multi-line set allows. The system administrator as well as the
extension numbers assigned to them configures the line appearances.
Standard Telephony Features Glossary
__________________________________________

24 World Wide Training Standard Telephony Features - 10/7/01 3:46 PM
Multiple Line Privacy provides the privacy feature for sets sharing a single-call
arrangement extension number. When a call is in progress on the extension number,
no other set on which the extension number appears can enter the call.
Music-on-hold some PBXs include an interface for MOH. Others use an adapter that
converts from the MOH player into an analog system connection. Optionally some of
the PBXs offer multiple MOH interfaces for Call Centers.
Mute allows the end-user on a speakerphone call to press a button and block the users
at the other end from the conversation. When the user presses the button again the
mute feature is turned off. The mute button must be configured by the system
administrator.

N
NANP - North American Numbering Plan
Night Mode/Service – allows Attendant Console to redirect calls to other locations
such as a station, another Attendant, an answering service, a night bell or other by
pressing a button, or some other method of initiating night mode. Some systems
support automatic Night Service.

NPA Area Codes, NXX Exchanges and XXXX Line Numbers
The process for assigning 10-digit (3+3+4) North American telephone numbers

Narrowband - Voice Grade - A low-capacity communications Circuit / path. It
usually implies a speed of 56Kbps or less. (Contrast with Wideband and Broadband)
NPA - Numbering Plan Areas
North American "Area Codes." (3 digits: 2-to-9, 0-or-1, 0-to-9. Middle digit to
expand soon)

NPA-NXX Routing
Area Code / Exchange Routing. Route calls based on the originating ANI NPA-NXX.

NPA Routing
Area Code Routing. Route calls based on the originating ANI NPA (area code.)

NPA Split
Subdividing an area code, with the creation of a new area code. This is necessary
when the number of telephones in an area code (NPA) grows to an excessive number.
NT1 - "Network Termination Type 1". The termination at the customer premises of an ISDN
BRI circuit. The NT1 performs the role of line termination of the “U – Interface” and
Code/Decodes from the line's 2B1Q coding scheme. The customer end of the NT1 interfaces
using the "S" or "T" interface.