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

beacon_dave over 4 years ago

There is a bit more info in the (8)746 model here:

https://www.britishtelephones.com/t746.htm

along with a wealth of other information.
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beacon_dave over 4 years ago
Couple of links about the UK PSTN switch-off in 2025.

Guidance: Protecting access to emergency organisations when there is a power cut at the customer’s premises
https://www.ofcom.org.uk/consultations-and-statements/category-2/access-emergency-organisations-power-cut

The closure of the public switched telephone network
https://www.crowncommercial.gov.uk/news/the-closure-of-the-public-switched-telephone-network

Sounds like Ofcom require that telephone service providers provide back-up solutions where required to ensure people can still call emergency services after moving to VOIP based telephony services.

Other systems requiring solutions to replace PSTN include:
- emergency phones in lifts
- home burglar alarms and security systems
- public traffic lights
- cash machines
- railway signals
- motorway signs
Interesting times ahead as they say.
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beacon_dave over 4 years ago

ZEBRA / elastomeric connector

https://en.wikipedia.org/wiki/Elastomeric_connector
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beacon_dave over 4 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
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beacon_dave over 4 years ago

How about a desk version of the Rotocell project ?

Episode 387: Rotocell - The Rotary Cell Phone of the Future!

/challenges-projects/element14-presents/project-videos/w/documents/4057/episode-387-rotocell---the-rotary-cell-phone-of-the-future
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