Post #2027308

2026-04-24 12:47 UTC

New Toy! It’s a “Ringer No 2A” which generated the tones, ringing current and timing pulses for small phone exchanges the UK They were commonly used in UAX13s (50-400ish lines) but did show up in other exchanges The middle third is a 50V DC motor The left third houses a series of notched wheels and magnetic pickups that generate tones (similar to a Hammond organ) On the right is a slowly rotating set of cams and contacts that chop them up into “ring-ring” etc I’ve wanted one for aaaages!

Replies (2)

@lpbkdotnet@mstdn.social 2026-04-24 12:52

(cont) Unfortunately I’m pretty busy with other stuff for the next few weeks, so won’t have a lot of time to get it running. Early indications are that it’s in good condition, but there is work to do before I can apply power… But when I do, there will be sound and (probably) video so you can experience it too!

Open ##2318540
@lpbkdotnet@mstdn.social 2026-04-30 06:10

I’ve made some progress on the Ringer 2A It’s now bolted to a bit of plywood, with its “U-Point” * connectors mounted on 3D printed standoffs I’ve got all the diagrams, and know which of the 64 connections are needed to make it chooch… I’ve just got to get it wired up and sort out a power supply with enough beef (6A of inductive load at 50V) to start it spinning! * I’ve no idea why they’re called “U-Points” - but if I say “back the right odds” a certain age of engineers brain will light up

Open ##2318541