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Modify a retired payphone so it can be used as a home telephone and for VoIP (Skype). Then learn how to modify the hacked payphone so it accepts quarters - and lastly, use a Redbox to make "free" phone calls from the modified coin-accepting payphone.
Length: 30 minutes
Here are some links for more information about payphone technology:
- Bell System Practices (essentially, the manuals for all Bell products) The BSP for payphones part 1 and part 2
- Bell System Memorial for older payphones and newer ones
- Mini Payphone controller part 1. And Part 2.
- Coin relay controller
Datasheets & parts notes
- MT8870 (and any other '8870 chips) DTMF decoder chips are available at Futurlec & BGMicro
- The telecom relay used is Tyco IM23TS, available at Digikey
- The DC/DC boost converter is LT1302
Schematics for the phone circuitry coming soon!
The Skype VOIP gateway-box used is a "USB-B2K", available online. We found that the D-Link DPH-50U used non-standard voltages and would not work with payphones (or many older phones for that matter) To make the B2K work, tip and ring were reversed (not shown in the video) since the payphone requires -48V.
Note that in this video, the phone line is connected to a VOIP box. If you're using a home phone line, leave the Black and Yellow wires disconnected ("floating") as they may be running a second line!
Electronics projects - Limor Fried & Phillip Torrone.
Intro and title graphics
Robert Hodgin, Flight404 "Solar with Lyrics" - made with Processing (open source programming).
Music (made with the x0xb0x, the open source TB-303 clone)
Mindblock - Ferrapsylix / Troy Sheets.
Live Jam - Resonator.
Easter Acid - Rusuden.
The Man with the Funky 303 - EvilXSystems.
Crisp Acid Day - Ceedub.
Fear the Robots - Jalcide.