AT&T System 75, Wiring Diagram

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CHAPTER 2. HARDWARE (66/110-Type)
188-Type Backboards
The 188-type backboards are wire troughs that channel the patch cords
or cross-connecting wire between the wiring blocks. The backboards
consist of a metal frame equipped with retaining rings. They are
available in four types:
●
●
●
●
The 188B1 backboard is a horizontal wire trough that is used with
110A-type terminal blocks.
The 188C2 backboard is a vertical wire trough that is used with
900-pair 110P-type terminal blocks.
The 188D2 backboard is a vertical wire trough that is used with
300-pair 110P-type terminal blocks.
The 188E2 backboard is a horizontal wire trough that is used
between the trunk/auxiliary field and the distribution field for
either 300- or 900-pair 110P-type terminal blocks.
188-TYPE BACKBOARD ORDERING INFORMATION
Description Comcode
188B1 Backboard
102 689 569
188C2 Backboard
104 031 794
188D2 Backboard
104 032 404
188E2 Backboard
104 031 802
Cords
110-Type Patch Cords
The 1-pair and 3-pair patch cords (Figure 2-9) are used to cross-connect
terminals to switch ports at the cross-connect field. The patch cords are
available in several lengths. The patch cords are equipped with a plastic
plug on each end. The plastic plugs are compatible with the 110-type
connecting blocks used on the wiring blocks. The patch cords are keyed
so that they cannot be inserted upside down or on a split pair.
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