AT&T 75 - Z1 A Emergency Transfer Unit

Z100-TYPE HARDWARE
Z1A Emergency Transfer Unit
Figure 2-91 shows wiring required at first (top) cable access panel for a voice terminal used
only for emergency transfer. These terminals are always connected from the port side of the
cross-connect field to connector X at the cable access panel. Figure 2-92 shows wiring
required at first cable access panel for a voice terminal used for emergency transfer as well
as a normal extension. Wiring at other cable access panels is the same for both type
installations except the power (PWR) leads must be connected to EM TRANS POWER
terminals on the first cable access panel.
If a Z1A Emergency Transfer Unit is used with central office trunks that require ground
start, a ground start switch must be installed on each emergency transfer terminal. System
ground is provided on the twenty-fifth pair of leads on each cable access panel connector on
the CABINET CABLES side when a cable is installed. System ground is connected to the
third pair of the 3-pair terminal appearance. This pair becomes the second pair at the
information outlet. A ground start switch is mounted on the side of the terminals and is
wired to ground and to the ring lead inside the terminal.
Requirements—Optional DID Make-Busy Trunk
Figure 2-93 shows the connections at the cable access panel for an optional Direct Inward
Dialing (DID) make-busy trunk. This option prevents DID trunks from being taken out of
service by the serving central office during emergency transfer. This trunk is used for this
function only and should be specified to appear on the twenty-fifth pair of a network
interface jack.
Installation—Terminals
Cable Access Panel Connections— Terminals Used Only for Emergency Failure Transfer
1.
2.
3.
4.
5.
6.
7.
At first cable access panel, run and connect pair of wires between PWR terminals
on EM XR terminal row to EM TRANS POWER terminal (see Figure 2-91).
Remove T and R straps for each central office (CO) trunk to be used for emergency
transfer.
Run and connect CO trunk circuit leads on CABINET CABLES side to TC
terminals on EM XR terminal row for each trunk.
Run and connect CO trunk circuit leads on DISTRIBUTION CABLES side to TK
terminals on EM XR terminal row for each trunk.
Connect terminal leads on X connector (see Note) to ST terminals on EM XR
terminal row for each emergency transfer terminal.
Note: Terminal leads appear on pairs 1, 4, 7, 10, 13, 16, 19, or 22 (the first
pair of any 3-pair group).
If ground start must be provided, run and connect two wires from G terminals to
third pair for each emergency terminal appearance on X connector. Loop the wires
from the first appearance to the last if enough ground (G) terminals are not
available (see Figure 2-94).
If more emergency transfer only terminals are to be installed, run and connect two
wires from PWR terminals on next cable access panel to EM TRANS POWER
terminals on first cable access panel and repeat from step 2.
2-130