AT&T System 75 Wiring Diagram page 240

PROTECTOR ORDERING INFORMATION
Description
3B1A (Carbon Block)
3B1E-W (Wide Gap Gas Tube)
3C1S (Solid State)
4B1C (Carbon Block with Heat Coil)
4B1E-W (Wide Gap Gas Tube with Heat Coil)
4C1S (Solid State with Heat Coil)
Data Link Protector (one ckt)
Data Link Protector (8 ckts)
SCP-1 Sneak Current Protector
79A Fuse (sneak current protector)
Figure 4-24 shows the connections for digital out-of-building voice terminals.
Miscellaneous Wiring Installation
Comcode
102 381 779
104 410 147
105 514 756
102 904 893
104 401 856
104 386 545
103 972 758
103 972 733
403 617 632
103 351 610
4-43