What's inside Rotary Electromechanical vs Pulse/Tone Phones? -- The Electronics Inside 52

Traditional landline phones are on the way out. By 2025, in the UK, they'll be dropped in favor of IP telephony. It seems like as good a time as any to tear down some telephones!

element14 Presents | About David| Project Videos | The Electronics Inside

Parents

beacon_dave over 3 years ago

Looks like you found the regulator diode pack and thermistors there.

https://en.wikipedia.org/wiki/GPO_telephones#Type_746

You've also got the 'new plan' BS 6312 plug there which works with the master socket arrangement which allowed people to start using their own phones on the GPO network. Before that there was a different jack plug arrangement along with its various old plan wiring arrangements.

https://en.wikipedia.org/wiki/File:GPO-plan4-telephone-socket-and-plug.jpg
- Cancel
- Vote Up 0 Vote Down
- Sign in to reply
- More
- Cancel
a531016 over 3 years ago in reply to beacon_dave

But I still have never understood why they didn't use the world wide standard of the RJ10 (or 14 depending on how many cores were actually needed). The master needs 2 cores from the exchange, internal wiring needed 3 cores to each socket. But each outlet to the device only used 2 (to the best of my knowledge)?
- Cancel
- Vote Up 0 Vote Down
- Sign in to reply
- More
- Cancel
beacon_dave over 3 years ago in reply to a531016

I would guess it was to dissuade you from plugging non BABT approved equipment into the BT phone network which at the time would have been considered illegal.

The 'new plan' appears to have been introduced to allow the user to purchase and to plug their own phone into the telephone network without the need for a BT engineer present. A BABT approved phone (with green circle sticker) would have been fitted with the new BS 6312 plug as standard.
- Cancel
- Vote Up 0 Vote Down
- Sign in to reply
- More
- Cancel
a531016 over 3 years ago in reply to beacon_dave

That's a good point. It feels a little "Apple using Lightning" to me?
- Cancel
- Vote Up 0 Vote Down
- Sign in to reply
- More
- Cancel

Comment

a531016 over 3 years ago in reply to beacon_dave

That's a good point. It feels a little "Apple using Lightning" to me?
- Cancel
- Vote Up 0 Vote Down
- Sign in to reply
- More
- Cancel

Children

No Data