AT&T 75 Wiring Manual page 373

Installing Loudspeaker Paging Access—278A Paging Adapter
Requirements
Figure 3-115 shows the connections for the Loudspeaker Paging feature. The connections are
for one zone. These connections are required for each paging zone.
The connections shown in Figure 3-115 and the procedures provided in this section are used
when the loudspeaker interface equipment is not located in the equipment room. If the
loudspeaker amplifier is located in the equipment room, the connections do not have to be
routed through the cross-connect field.
Access to loudspeaker paging is provided by an information outlet. The switch side of the
cross-connect field is connected to a 278A adapter. The adapter must be modified with a D-
181321 kit of parts for -48V powering. The adapter is mounted in the auxiliary cabinet, if
provided. Six leads (T, R, SZ, SZ1, S, and S1) connect the 278A adapter to a TN763 Auxiliary
Trunk circuit pack located in a port carrier. A TN763 circuit pack contains a maximum of
four ports.
Installation
Note: If auxiliary cabinet is not provided, a connectorized wiring block must be locally
engineered to replace the auxiliary cabinet's ED-1E443-10 Intra-Connection Panel.
1 . Determine port assignment of paging zone(s) from Loudspeaker Paging Form:
2 . Identify carrier slot and label both ends of an A25D cable.
3 . Run and connect A25D cable from assigned port carrier slot to 25-pair connector
on auxiliary cabinet's ED-1E443-10 Intra-Connection Panel (see Figure 3-115).
4 . Run and connect A25D cable from 25-pair connector on ED-1E443-10 Intra-
Connection Panel to switch side of cross-connect field (see Figure 3-115).
Install yellow (auxiliary) label on 110 terminal block.
5 .
6 . Mount 278A adapter.
7. Remove cover from 278A adapter and make connections to 110-type wiring blocks
on ED-lE443-10 Intra-Connection Panel (see Figure 3-115).
8 . On 278A adapter, connect BZ2 terminal to -V terminal, if required.
9 . Connect -24V and GRD terminals on 278A adapter with at least a -24V 40-ma
power supply. If the auxiliary cabinet is providing the power, then a D-181321 kit is
required to reduce the -48V to -24V.
Install straps between E and F terminals and G and H terminals for the first 278A
1 0 .
adapter. Install option straps between C and D terminals for each 278A adapter.
1 1 . Install cover on 278A adapter.
1 2 . Install patch cord or jumper wires at cross-connect field.
1 3 .
Connect 2-pair line cord (modular plug at one end) from information outlet to
loudspeaker system (see Figure 3-115).
EXAMPLE: Port Number
110-TYPE HARDWARE
B
02 01
Carrier Slot Circuit
3-157