AT&T System 75, Wiring Diagram

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Typical System Equipment Room Floor Plans
Wall Space Requirements for 110-Type Hardware
The trunk/auxiliary field and the distribution field are mounted on the
same wall. Each 110P-type terminal block is 8-1/2 inches wide. Vertical
patch cord troughs are 5-5/16 inches wide and horizontal patch cord
troughs are 23 inches wide.
Each 110A-type terminal block is 10-13/16 inches wide; however, no
horizontal patch cord troughs are used and the blocks are shorter than
110P-type terminal blocks. This allows the 110A-type terminal blocks to
be stacked. Therefore, the 110A-type hardware requires less space
than the 110P-type hardware on a per-station basis.
Wall Space Requirements for 66-Type Hardware
The trunk/auxiliary field and the distribution field are mounted on the
same wall.
If the 66-type connecting blocks are being mounted directly on a wall,
the space requirements of a 183-type backboard should be used to
figure the amount of wall space required for the connecting blocks. This
method allows enough space between the connecting blocks for jumper
wires and cable connections. The 183A-type backboard mounts four
66-type connecting blocks and is 8-1/2 inches wide and 20 inches tall.
The 183B-type backboard mounts eight 66-type connecting blocks, and
is 17 inches wide and 20 inches tall.
When multiple mountings are required, each 166-type mounting is 17
inches wide and 20 inches tall, and each 154A-type mounting is 8-1/2
inches wide and 20 inches tall.
The 187B1 backboard, equipped with pegs, is 17 inches wide and 6-1/2
inches tall.
Equipment Requirements
Cable Slack Manager Requirements
A cable slack manager is 32 inches wide. The quantity of cable slack
managers required is determined by dividing the total length of the
cross-connect field (in inches) by 32. A partial number of .4 or less
should be rounded down, and a partial number of .5 or more should be
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