AT&T System 75, Wiring Diagram

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Associated Hardware
Trunk Concentrator Cables
Trunk concentrator cables are used for the following purposes:
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To match 1-pair local telephone company trunks to 3-pair switch
circuits at the cross-connect field.
To match 1-pair local telephone company trunks provided for
off-premises lines to 3-pair switch circuits at the cross-connect
field.
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To split eight 3-pair analog tie trunks into two groups of four
3-pair tie trunks.
The trunk concentrator cables are 25 feet long. They are coded as cable
assemblies and described in the following sections.
Note: The WP-90929, List 1 and List 3 cable assemblies are used
with 110-type hardware, while List 2 and 4 cable assemblies are
used with 66-type hardware.
WP-90929, List 1, Cable Assembly (For 110-type Hardware Only)
The WP-90929, List 1, cable assembly (Figure 2-20 and Table 2-B)
provides a way to connect local telephone company trunks to the
switch. It can also be used to connect off-premises analog trunks
between the port field and trunk field at the equipment room
cross-connect field. All the ribbon connectors on the cable assembly
are male-type connectors. Each cable assembly can match twenty-four
1-pair trunk circuits with twenty-four 3-pair trunk circuits.
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