AT&T 75 Wiring Manual page 527

2.
Run and connect CO trunk circuit leads from the purple field to TC terminals on
the yellow emergency transfer connecting block for each trunk.
Run and connect CO trunk circuit leads from the green field to TK terminals on
3.
the yellow emergency transfer connecting block for each trunk.
4.
Connect the ST terminal leads on the yellow emergency transfer connecting block
for each emergency transfer terminal to the terminal appearance in the yellow
Trunk/Auxiliary Field (see Note).
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).
5. Connect the terminal appearance in the yellow field to the blue or white station
distribution field.
66-TYPE HARDWARE
4-101