Add Channel Service Units
Installing the 120A3A CSU
652
SI Installation and Upgrades
June 2004
H700-383-Equivalent Cable Guidelines
If using cabling other than the H700-383 provided with the 120A3A, observe the following guidelines:
•
Use 24-gauge wire that provides individually shielded, twisted pairs for transmit and receive
signals. Use the cable between the network interface and the 120A3A. Ground the shields of this
cable only at the 120A3A end to avoid ground loops.
•
Cabling between the network interface and 120A3A can have no bridge taps.
•
If using standard house riser cable for connections between the network interface and the
120A3A, maintain a 100-pair separation between the receive and transmit twisted pairs.
•
If using standard house riser cable for connections between the network interface and the
120A3A, allow no more than 2 cross connects to 110-type cross connect blocks.
•
Never use quad cable (untwisted two pair telephone cable) in a DS1 line.
•
Avoid mixing wires of different gauges in a DS1 line.
Installing the 120A3A CSU
Figure 260, 120A3A Channel Service Unit Module,
on page 653 shows the connection points.
NOTE:
Re-manufactured/repaired ICSU units and any manufactured after May 7, 2002 are
marked as “120A3A.”
CAUTION:
Do not plug the 120A3A into any circuit packs other than a TN464F or TN767E (or later),
or TN2464BP or TN2313/AP. Do not connect the 120A3A to any interface other than
700A DS1 loopback jack.
Be sure the DS1 circuit pack is set for 24-channel operation (1.544 Mbps). The 120A3A
does not operate with the 32-channel interface. A switch on the circuit pack or
administration sets this option.
1
Always wear an anti-static wrist strap when installing a 120A3A module. Do not touch the
external alarm cable when it is connected to the 120A3A. Static discharge can damage connector
terminals and relays.
2
Unplug the DS1 circuit pack from its slot.
3
Install a 4C retainer in the 50-pin plug associated with the DS1 circuit pack slot.
4
Plug the 25-pair connector on the 120A3A directly into the plug associated with the DS1 circuit
pack slot.
5
Secure the 4C retainer around the 120A3A.
6
Attach the supplied H700-383 cable to the 120A3A and to the 700A loopback jack.
This cable is directional. To determine the end that connects to the 120A3A, perform a continuity
test between pins 3 and 7. The end with this continuity is the 120A3A end. The shield is grounded
only at the 120A3A end.
Use the cable provided. If using cabling other than that provided with the 120A3A, see
H700-
383-Equivalent Cable Guidelines
on page 652.