View Single Post
Old 28th Jul 2019, 2:16 pm   #14
TonyDuell
Dekatron
 
Join Date: Jun 2015
Location: Biggin Hill, London, UK.
Posts: 5,190
Default Re: Vintage Arrow ( Toy? ) Telephones

As promised here are some reverse-engineered circuits of similar telephones in my collection. They're all similar (and similar to the circuit Julie posted). It's quite an old design, I've found much the same circuit in books over 100 years old.

All mine have some kind of calling button to connect the battery directly to the line to sound the buzzer/bell at the other end.

One thing I'd not thought of was putting the transmitter (microphone) and receiver (earpiece) in parallel (one of mine is wired like that). It will work and it might be possible to have components with a low enough resistance to be able to sound the buzzer with the handest in-circuit, as suggested in an earlier post.
Attached Files
File Type: pdf toy_intercom_telephones.pdf (692.1 KB, 77 views)
TonyDuell is online now