Joe's Corner
  • Home
  • Telephones
    • Conversion Information
    • A Homemade LD-DTMF Converter
    • Ringing Detector
    • Untangling Curly Handset Cords
    • Microphones
    • Dial Labels
    • ITI 332 Diagram
    • ATM T3903 (232-Like Mine Telephone)
    • An Un-Natural Union Between a 232 and a 746
    • Rebuilding an Indian Candle-Stick
    • Telephone Set 'J' Repair
    • Taking a Tribune to Bits
  • Electronics
    • The LM386
    • The LM317
    • PCB-Making Tips
    • Headphone Amplifier
    • Continuity Tester
    • Bench Power Supply
    • AVO INS Range Power Supply
    • µA741/Transistor Amplifier
    • µA741/EL84 Audio Amplifier
    • EF80/EL84 Audio Amplifier
    • Toko Coil Data
  • Woodwork
    • Market Stick
    • Another Market(ish) Stick
    • Dachshund Tie Rack
    • Travel Cribbage Board
    • Computer Speaker Number Two
    • French Polishing
    • Dutch Tool Chest
    • Home-Made Tools
    • Tenon Saw Restoration
    • Plane and Drill Repair
    • Acorn No 4 Plane Overhaul
    • Turning
  • Vintage Radios
    • Repair Stories
    • Old Battery Labels
    • Connecting an MP3 Player &c to a Vintage Radio
    • Battery Eliminator
    • Valve Factory Codes
    • Radio and Television Servicing Index
  • Clocks
    • Wall Clock
    • English Cuckoo Clock
    • Smith's Marine Clock
    • Ferranti Electric Clock
    • Goblin Model 46 Electric Clock
    • "RAF Sector Station Clock"
  • Computers
    • Linux >
      • Wine Hints
      • Fixes
      • Using Windows Sreensavers on Linux
      • Accessing Non-Passworded Windows Shares
    • Android >
      • Blocking Adverts
      • ES File Explorer
    • Arduino
    • Pi SD Card Tasks
    • Old Keyboards
    • Fun with Cloud Storage
    • The Sad Story of Google Chrome
    • Belkin Wireless Extender
    • Computer Speaker
    • Printing from DOS to USB Printers
    • Favourite Software
  • Engineering
    • Yankee Screwdriver Hex Bit Adapter
  • Jeyes Fluid
  • Recipes
  • School/College Memoirs
  • Quotations
  • Links
    • AVO Information
    • eBooks
    • Vintage Radio Related
    • Telephone Related
Telephone Ringing
​Detector


I’ve called this a ringing detector for want of a better name, and it certainly seems to be a widely used term for such things. A better description would be a relay that is operated by telephone ringing current.

I wanted a telephone bell that I could hear when I was outside, and particularly when I’m in a shed.

Exterior bells, both ‘Vintage’ and new are available but they need paying for and that is against my religion. I had got a 12V fire-bell which would be ideal if I could interface it to the telephone line.

This is what I came up with, which didn’t cost me anything as they were all parts I’d got; IC1 came out of an old power supply:--
Picture
When JP1 is open the relay pulls in and drops out 25 times a second, which works best with my bell. With it linked C2 smoothes out the bumps so the relay stays in while ever the telephone is ringing.

The numbering of BT-style plugs and sockets is plain insane. The numbers on the diagram are those that would be found on the back of a socket. The plugs are numbered backwards though so that socket terminal 5 connects to plug terminal 2, 4 to 3, 3 to 4 and 5 to 2. Plugs are numbered starting at the side furthest from the lever and, to add to the fun, terminals 1 and 6 are usually not fitted. Therefore counting from the lever, and assuming the plug only has four contacts, this devise should be connected between the second and fourth contacts.

If you’re re-using an old cord these SHOULD be the blue and white wires. If it uses the American colours it will be green and black. It's best to check with a continuity tester or ohmmeter though.

As well as ringing bell it could be used to flash a light in noisy environments or if you listen to music with headphones so can’t hear a telephone ring.

PCB Details:--
Picture
Picture
These images are available as PNG files in a ZIP here.
Powered by Create your own unique website with customizable templates.