AT&T System 75 Wiring Diagram page 278

CHAPTER 5. AUXILIARY EQUIPMENT INSTALLATION
Installing Loudspeaker Paging Access—278A Paging
Adapter
Requirements
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 27A adapter is designed to operate on -24V dc. If it is to be
operated on -48V dc, it must be modified with a D-181321 kit of parts.
The adapter is mounted in the auxiliary cabinet, if one is available. If an
auxiliary cabinet is not available, a connectorized wiring block must be
locally engineered to replace the auxiliary cabinet ED-1E443-10
intra-connection panel. Six leads (T, R, SZ, SZ1, S, and S1) connect the
adapter to a TN763 auxiliary trunk circuit pack located in a port carrier.
A TN763 circuit pack contains four ports.
Figure 5-2 shows the connections for the Loudspeaker Paging feature.
The connections are for one zone. Repeat the connections for each
paging zone.
The connections shown in Figure 5-2 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.
5-5