AT&T System 75, Wiring Diagram

Page: 250 / 345

Miscellaneous Wiring Installation
Note: The ST terminal leads should be terminated on the
following pairs: 1, 4, 7, 10, 13, 16, 19, or 22 (the first pair of any
3-pair group).
Connect the ST leads from the terminal selected in Step 4 to the
assigned terminal in the blue or white station distribution field.
5.
Trunk/Auxiliary Field Connections—Telephone Used for Emergency
Transfer and as a Normal Extension
Connect telephone as follows:
At trunk/auxiliary field, connect a pair of wires between the -48V and
GRD terminals on the yellow emergency transfer row/connecting block
to the EM TRANS RELAY PWR terminal (Figures 4-26 and 4-27,
respectively for 110-type and 66-type hardware).
1.
2.
3.
4.
5.
Connect CO trunk leads from the purple field to TC terminals on the
yellow emergency transfer row/connecting block for each trunk.
Connect CO trunk leads from the green field to TK terminals on the
yellow emergency transfer row/connecting block for each trunk.
Connect telephone leads from the purple analog line board
row/connecting block to the LC terminals on the yellow emergency
transfer row/connecting block for each telephone.
Connect ST leads on the yellow emergency transfer row/connecting
block for each emergency transfer telephone to the ST terminal
appearance in the purple trunk/auxiliary field.
Connect the ST leads from the terminal selected in Step 4 to the
Telephone Installation
Install telephone assigned to emergency transfer as follows:
assigned terminal in the blue or white station distribution field.
Connect telephone to the information outlet.
Install patch cords/jumper wires between the switch side and the
station side of the station distribution cross-connect field.
1 .
2 .
4-53