Tài liệu DSX-3 Cable and Cross-Connect Limits pptx

Overview
The DSX-3 is a common point in central offices or network nodes that provides the
following functions:
• Termination of a variety of equipment referred to as network elements (NE). The NE
are permanently cabled to this common point during the initial installation and remain
terminated at the DSX-3 for the life of the equipment.
• Cross-connection of two NE together to configure a circuit. The cross-connect jumper is
a semi-permanent connection that may be changed as the telephone network evolves and
circuits are re-configured to meet service demands. As new equipment is introduced into
the network, this replaceable jumper facilitates a means to re-connect equipment together
throughout the continuous upgrade of equipment.
• Access of circuits by means of jacks. Jack access provides a means to:
- Test circuits when a failure occurs and sectionalize portions of the circuit to determine
which NE is defective.
- Patch around the failed NE to quickly restore service until the defective NE is repaired.
- Patch existing NE to new NE during cutovers when portions of the network are upgraded
to a new technology of equipment. After the patch is made, the old jumper is removed
and a new jumper is added to connect old and new NE together and then the patch is
removed.It is important to understand that based on the application, the appropriate
module must be utilized to ensure proper signal monitoring. The following diagram
illustrates the difference between each module.
To accomplish the flexibility of this system, an equal level point (ELP) must be established at the
DSX-3. The ELP ensures that signals from all NE are at the same amplitude and signal strength at
this common cross-connect and access point; the DSX-3. When a common ELP is established, any
two NE may be connected together without re-adjusting the signal strength. Furthermore, when
circuits are re-configured during the evolution of the network, re-adjustment of NE is not required.
DSX-3
Cable and Cross-Connect Limits
application note
2
www.adc.com • +1-952-938-8080 • 1-800-366-3891

3/01 • 1228
DSX-3 Cable and Cross-Connect Limits
Original Specs
CB119, Bell Laboratory compatibility bulletin, defined the standard ELP pulse template. An end to end
maximum budget loss of 12.15 dB.between any two NE consisted of: 5.5 dB (450' of “728A” type
equipment cable) between the NE and DSX-3 and 1.15 dB (27' of “RG59” type cross-connect jumper)
between DSX-3 terminations as shown in Figure 1.
DSX
728A
450'
5.5 dB
DSX
728A
450'
5.5 dB
RG59
27'
1.15 dB
NETWORK
ELEMENT
NETWORK
ELEMENT
Figure 1
CB119 Cable and Cross-Connect Limits
As networks evolved, and the high bandwidth demand of DS3 service expanded, DSX-3 systems have
often grown beyond the physical limitations set forth by the 728A cable and RG59 cross-connect. The
physical diameter of the cable congested cable and cross-connect routes within the central office. Also,
DSX-3 system capacity is limited by the allowable cross-connect jumper length and the maximum
number of modules placed within that maximum length.
734A type cable, with a smaller diameter and equal electrical characteristics, soon became the

equipment cable standard. This cable still caused cable congestion in the central office as demand for
DS3 service exploded.
Newer Cables
The use of 735A type cable and cross-connect jumpers, dramatically reduces cable congestion, but also
reduces the length of transmission. A study of central offices determined that 90% of NE can be cabled
to the DSX-3 within the limitation of 735A cable at 225'. 735A cable and cross-connect limits are shown
in Figure 2.
DSX
735A
225'
5.5 dB
DSX
735A
225'
5.5 dB
735A
20'
1.15 dB
NETWORK
ELEMENT
NETWORK
ELEMENT
Figure 2
735A Cable and Cross-Connect Limits
3
www.adc.com • +1-952-938-8080 • 1-800-366-3891
3/01 • 1228
DSX-3 Cable and Cross-Connect Limits
Proposed Limits
The 20' limitation of 735A cross-connect jumpers restricts the system capacity of the DSX-3. The high

growth rate of DS3 service has prompted ADC to expand the DSX-3 capacity by engineering high
density DSX-3 modules and extending the cross-connect limits.
The proposed cable and cross-connect limits to expand DSX-3 capacity are shown in Figure 3.
DSX
735A
200'
5.0 dB
DSX
735A
200'
5.0 dB
735A
60'
2.15 dB
NETWORK
ELEMENT
NETWORK
ELEMENT
Figure 3
Proposed 735A Cable and Cross-Connect Limits
In addition to extending cross-connect limits, ADC’s Mini-DSX-3 provides the highest capacity DSX-3
solution. The high density design of Mini-DSX-3 can double or triple system capacity when compared
to traditional 24 or 16 termination chassis as shown in Figure 4. The modular Mini-DSX-3 terminates
48 DS3 network elements in a single 23" chassis.
Figure 4
DSX-3 Maximum System Capacity
Based on Single Line-Up with Ten Chassis Per Bay
Terminations
per Chassis
16

24
48
60' Cross-Connect
17 Bays
2720
4080
8160
20' Cross-connect
4 bays
640
960
1920
Cross-Connect Design Length
The maximum cross-connect length within a given DSX-3 system must reach from the top of the first
bay to the bottom of the last bay of a line-up to ensure that any two NE may be cross-connected
together as shown in Figure 5.
ADC Telecommunications, Inc., P.O. Box 1101, Minneapolis, Minnesota USA 55440-1101
Specifications published here are current as of the date of publication of this document. Because we are continuously improving our products, ADC
reserves the right to change specifications without prior notice. At any time, you may verify product specifications by contacting our headquarters
office in Minneapolis. ADC Telecommunications, Inc. views its patent portfolio as an important corporate asset and vigorously enforces its patents.
Products or features contained herein may be covered by one or more U.S. or foreign patents. An Equal Opportunity Employer
1228 3/01 Revision © 1998, 2001 ADC Telecommunications, Inc. All Rights Reserved
Web Site: www.adc.com
From North America, Call Toll Free: 1-800-366-3891, Ext. 63475 • Outside of North America: +1-952-938-8080 Fax: +1-952-946-3292
For a complete listing of ADC's global sales office locations, please refer to our web site.
CHASSIS 9
CHASSIS 8
CHASSIS 7
CHASSIS 2
CHASSIS 1

CHASSIS 4
CHASSIS 3
CHASSIS 6
CHASSIS 5
CHASSIS 9
CHASSIS 8
CHASSIS 7
CHASSIS 2
CHASSIS 1
CHASSIS 4
CHASSIS 3
CHASSIS 6
CHASSIS 5
CHASSIS 9
CHASSIS 8
CHASSIS 7
CHASSIS 2
CHASSIS 1
CHASSIS 4
CHASSIS 3
CHASSIS 6
CHASSIS 5
CHASSIS 9
CHASSIS 8
CHASSIS 7
CHASSIS 2
CHASSIS 1
CHASSIS 4
CHASSIS 3
CHASSIS 6

CHASSIS 5
26"5" 26"10" 26" 26"10"10" 5"
CABLE TROUGH CABLE TROUGH CABLE TROUGH CABLE TROUGH
CABLE TROUGHCABLE TROUGH
CHASSIS 10
FUSE PANEL
CHASSIS 10
FUSE PANEL
CHASSIS 10 CHASSIS 10
CABLE TROUGH CABLE TROUGH
FUSE PANEL FUSE PANEL
Figure 5
Typical System Cross-Connect Design Length