Is this a poor mans hold button ?

[Dan/Panther]

I have this WE500 with one white plunger that stays up when you lift it. Is it a hold button, or what is it for ?
D/P

[Dennis Markham]

I "think" it is an exclusion button.  I don't have one so I'm going by what I've read.  I think if you pull it up you can listen in and have a conversation in the room without the other person hearing you.  When you push the button down then you can have conversation (on the phone)---or the other way around.

[Steve K]

Yes it is an exclusion key.  Some may work the way Dennis suggested but they were also used to prevent people from listening in on other phones that were connected to the same line.

Steve

[Steve]

Sort of like a "down low" button? LOL! no more, MOM HANG UP!

I could have used one like that back in the early seventies ..

[Dan/Panther]

My next question, does the system need to be wired to accomodate the plunger, or will it just work on any multi phone setup ?
Can I just plug it into my house phone system, and it's going to work, or do you have to have special wiring for it ?
D/P

[Steve K]

You need to have the house phone system wired for an exclusion circuit.

[Bill]

Well wait a minute. There are two kinds of "exclusion" discussed above. Dennis described one in which the transmitter is simply disconnected. This would be accomplished right in the phone.

Steve K described one in which other phones on the same circuit were disconnected from the circuit. This would require a more elaborate apparatus in a remote location, and could not be accomplished in the phone. In addition, it would require at least one more wire running from the phone to the apparatus.

D/P, you'll have to tell us how it is wired. But either way, it is not a Hold button.

Bill

[Steve K]

If it is a single line phone it would have to be wired sort of like a GFI electrical circuit.  All the phones to be excluded would be on a line terminating at the phone with the exclusion button.  Of course that phone would have to have a 4 conductor line cord.

Steve

[Dennis Markham]

It should say on the bottom what model it is.  Is it a newer version of the 501 F seen here?

http://www.paul-f.com/we500typ.htm

[Dan/Panther]

It's marked A/B-502  (6-69). It has a 6 conductor line cord, Paul's reference calls it "Extension Exclusion Set".
D/P

[Steve K]

OK, then you should be able to wire it like I said.  Two leads will be the tip and ring from the main line, two leads will be the tip and ring going to the other phones and the remaining teo leads are the A-lead control lines if you were using a 1A2 key setup.  If you don't have the key system you do not need to connect those last two wires.

Steve

[Dan/Panther]

Interesting, Thanks, can't wait to see if I can get it to work.
D/P

[GG]

Yes, that's an exclusion key, the purpose of which was to exclude other extensions from access to the line in order to prevent casual listening-in. 

The CO line comes into the building, and is first connected to the phone with the exclusion key, and passes through the key switch, exits the phone, and goes on to the other extensions on the line. 

On WE and equivalent (ITT, SC) sets, the key had a set of leaf springs consisting of one SPST switch and one SPDT switch.  When the key was pulled up, the SPST switch would open one side of the line to the extensions.  The SPDT switch would open the other side of the line and then use its "make" contact to short the extensions downstream to prevent leakage of the speech current to them. 

AE used a set of two colored plungers for this.  The old 80 series (type 85, there were A through D depending on whether they had an exclusion key or a turn-button or both) used red for exclude and chrome for restore.  The 80-E variant was a 2-line set where the "exclusion" buttons were actually wired to holding bridges so it would place both lines on hold at the same time (and then you could use the turn-button to switch between conversations). 

Exclusion does not work for modular phones because if you unplug the primary set, it disconnects the extensions.   Thus AE just used the buttons to do something else entirely, in this case, 2-line hold.