ITT 500 2 line

[bushman]

I picked up this 74 ITT 2 line a while back. I noticed while cleaning it that there is another set of contacts under the white receiver plunger. Can anyone tell me what this was used for?

Bushman

[Wallphone]

Here is the WE version  -  > http://www.paul-f.com/we500F.html <
Dougpav

[keysys]

It's most likely a simple hold key.  Lift the plunger before using the twist key to switch between the two lines.  Hold condition is removed when the plunger is restored to normal, as when the handset is replaced in its cradle.

A similar plunger and contact arrangement was also used to provide "exclusion", a privacy feature.  The user could lift the plunger before dialing a call, or at any time during a call, and all other extensions connected to the same line would be excluded for the duration of the call.

[bushman]

I will pull it back down again when I start polishing. I will try to trace the wires from that contact switch and log down where they go and post the results.

Bushman

[LarryInMichigan]

I remember decades ago when we had two lines in our house and had phones with plungers like that.  The purpose was to hold a call on one line when switching to the other line.  If the plunger was not pulled before turning the line switch, the first call would be dropped.

Larry