Author Topic: Ringer on WE 354  (Read 300 times)

Offline RDub

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Ringer on WE 354
« on: October 11, 2016, 05:13:42 PM »
I'm brand new here and have a few questions about a WE 354 telephone. This more than likely applies to all land line phones. I stripped down the 354 and cleaned everything up. Have it back together less the handset and handset leads. Wanted to test the ringer so I hooked it up to my analyzer. Ringer worked but would not disconnect when I lifted the hook switch. Checked the circuit portion for the ringer but don't understand how it gets disconnected from the circuit when you lift the hook switch. (?) Do I need to have the handset wired in to get the ringer to stop? I wouldn't think so but what do I know. ;D just trying to understand the circuit. RDub...

Offline poplar1

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Re: Ringer on WE 354
« Reply #1 on: October 11, 2016, 05:28:07 PM »
The ringer is always connected in the 354, whether the phone is "on-hook" (handset in the cradle) or "off-hook." You just need to connect the handset again, and the phone should work properly (i.e., stop ringing when you answer).

Since you don't have the handset wired in, then even though you lift the hookswitch, the phone will still ring (at least most models from this era), because to the central office equipment (landline), it appears that the phone is still hung up.

When you answer a phone (if fully assembled), then you "trip" the ringing and the phone stops ringing.

The ringer is in series with a capacitor that blocks DC (direct current) so that it doesn't keep your line off-hook (busy). When you go off-hook, once your handset is wired up again, that will complete a DC path through the talk circuit of your phone. The central office equipment detects the off-hook condition, interrupts the ringing and connects you to the calling party.
"C'est pas une restauration, c'est une rénovation."--François Martin.

unbeldi

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Re: Ringer on WE 354
« Reply #2 on: October 11, 2016, 05:35:15 PM »
What you are describing is quite correct.  The ringer is permanently connected to the line, even during a telephone call.

When the user takes the handset off the hook, the telephone completes the local loop circuit, which carries direct current.  The telephone exchange detect the current flow and shuts off the ringing signal, which is alternating current.

The reason the ringer can stay connected is that the ringers of most new equipment starting in the mid 1930s have a high impedance, or AC resistance, which is over one hundred kilo-ohms at voice frequencies, so that the ringer essentially does not diminish the speech signals.  Previously, before that time, ringers in general had a much lower impedance, and many telephone manufacturers indeed did disconnect the ringer when the handset was off-hook.

Offline RDub

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Re: Ringer on WE 354
« Reply #3 on: October 11, 2016, 07:32:04 PM »
Thanks guys. Your explanations made it perfectly clear. Give me a few days and I will have more questions to ask... RDub