Class of service wiring in a WE Trimline

[RotoTech99]

Dear CRPF:

What class of service would have the black ringer wire on terminal 3 of a Trimline desk base terminal board instead of on L1, please?

The red ringer lead is on K on the terminal board.

I'm guessing for party line service, but what type of party line service, I'm not sure...

I know party line service is a "dead" service nowadays, but I'm still curious.

If CRPF can answer this, I would appreciate it.

Thanks,
RotoTech99

[poplar1]

Black ringer wire on 3 is for 2-party line. Mounting cord jack yellow wire goes to 3, black to 4. For tip party, tip (green) to L2 and ring (red) to L1. For ring party, tip to L1 and ring to L2.

Transformer goes to yellow and black mtg. cord conductors (white and black on old-style cord).

Ref: BSP Section 502-303-101 Issue 4, March 1975, Table D.

[RotoTech99]

Dear Poplar1:

HI, that's what I figured it might be, asking is usually the best way to find out.

RotoTech99