sundance-communications.com/forum Forums Other TDM Phone Systems 1A2 and Comkey Telephones & Systems A lead control

Greetings,
For the life of me I can't remember how to wire a 255447-MBA-20M-11-89-A for A lead control it is a USA made Cortelco set. Any help would be appreciated.
TYIA,
John

ITT sets used the slate/white and slate/green switch hook leads for A lead. Move the green line cord lead and the black ringer lead from terminal L1 to terminal F on the network. Pull the slate/white and slate/green leads from these terminals and connect them to the black and yellow line cord leads via blind terminals, such as L1 and G.

Thanks Ed this phone is set up slightly different. The switch hook leads are: Slate and Slate/yellow on A with the red of the line cord. Slate/white to the keypad Slate/red to the keypad Slate/black on R Slate/green on L2 Line cord green on L2. So I'm not sure which one to use?
Thanks,
John

Ed, the way you remember this stuff is a sure sign you need help.,.....

WECO sets used the slate/yellow and slate/brown for A-leads, while ITT for some reason used slate/white and slate/green. The key is that these are both normally open switch hook contact pairs, but one makes/breaks before the other.

I know that the newer electronic dial pads resulted in slightly different network wiring, but it's all the same at the end of the day.

You basically have to jump around the two terminals where the slate/white and slate/green wires land. For example, if slate/white is on terminal A and slate/green is on terminal B, then you remove both wires and place a jumper to bridge terminals A and B. You then use two blind terminals to join this switch hook pair to the yellow/black line cord leads.

There are several blind terminals on the 425 type network that you can use unless they are already in use. L1, L2, G, E1 and E2 are your best bet.

The slate/red and slate/black switch hook leads are just a set of contacts that short the handset receiver when hanging up to reduce the loud click that would otherwise be heard. There's no need to mess with these.

Oh, and thanks Ken for your vote of confidence. My therapist will enjoy your comment!