BT 8746 telephone question

[cowjam_]

Hello! I've just registered as this seems a perfect place for my question:

I've got a BT 8746 rotary dial telephone that I'm using as part of an electronics project. I'd like to make it ring, I've found the relevant connection points but I what voltage and current is it expecting?

I'm making it into a speaking clock - pick up the receiver and it'll tell you the time. I'd also like to be able to add alarms to it, which is why I want it to ring.

Thanks.

[Pellseinydd]

Originally Posted by cowjam_

Hello! I've just registered as this seems a perfect place for my question:

I've got a BT 8746 rotary dial telephone that I'm using as part of an electronics project. I'd like to make it ring, I've found the relevant connection points but I what voltage and current is it expecting?

I'm making it into a speaking clock - pick up the receiver and it'll tell you the time. I'd also like to be able to add alarms to it, which is why I want it to ring.

Thanks.

66 volts ,25Hz A/C or thereabouts and current a few mlliamps for several bells.
See here for more info about various GPO/PO/BT 'Ringing Converters'.

You'll find and old GPO 'Speaking Clock' of the 1960's on 01352 83 8081 - usually in your free landline/mobile free calls package -not a premium rate number.

'8081' was the code for the Speaking Clock prior to it becoming '123' except for 'Director' areas where it used to be 846 ('TIM').

Good luck with the project.

[cowjam_]

Thanks for the info. I'm not proficient enough to know how to change 3v DC to 66v AC, so I've replaced the ringer mechanism with a very small motor and two washers on a bit of thread as a flail, and it works well enough.

Here's a very brief video of it working:https://youtu.be/ePLxMWLDkbY

Thank you for your help