AT&T System 75, Wiring Diagram

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CHAPTER 4. STATION WIRING
Installing Customer-Provided Alarm—System 75 XE Only
Requirements
The switch provides access to a relay contact that can be used to
operate a customer-provided alarm, such as a light, bell, or similar type
device. The relay contact can be administered so that it makes contact
when a major, minor, or warning alarm condition exists in the switch.
The circuitry required for this feature must be provided by the customer.
The device, connected to the alarm leads, must not exceed a rating of
more than 100 volts at 3/4 amp. The contact leads appear at the
cross-connect field on the AUXILIARY connector. Refer to Table 3-H for
the AUXILIARY connector lead assignments.
Installing Off-Premises Station Wiring
Requirements
The cabling outside the building for off-premises stations is provided by
the local telephone company. The off-premises stations can appear on
any of the RJ21X network interfaces provided for CO trunks. Only a
FCC approved analog type telephone, for example, a 2500-type, can be
used as an off-premises station. Figure 4-21 shows the connections for
OFF-PREMISES
TERMINAL
2500
500 (R1V2)
SNEAK
FUSE
PANEL
PART OF CROSS-CONNECT FIELD
TRUNK SIDE
SWITCH SIDE
T,R
T
R
TN742 OR
TN769
CIRCUIT
PACK
PORT
JUMPERS
GREEN PURPLE
*A25D
FIELD
FIELD
OR
RJ21X
†B25A
NETWORK
CABLE
INTERFACE
* USE WITH 11O-TYPE TERMINAL BLOCK
† USE WITH 66-TYPE CONNECTING BLOCK
Figure 4-21. Connections For Off-Premises Stations
4-36