Conference Call Radio Station

Conference Call Radio Station

Secret music listen


This device plugs into a work telephone system, as iPod also plugs in, and a telephone headset. You then ‘turn’ the sticktape to activate a switch, which would change your headset from connecting to the phone (to make calls) or to listen to your iPod, while everyone in the office just thinks you have a headset on.

Telephone Conference Radio with Main Unit and iPhone and Headset

Tape Dispenser


All the circuit was concealed inside the tape dispenser, this is so it would site next to the telephone and no one would notice.

The 0 and 1 on the front was my ‘on/off’ switch indicator, and you’d push the tape in the direction to connect the headset to the phone, or to the music.

Telephone Conference Radio close up of the tape dispenser sockets that plug into the phone and the headset front of unit

Connections


On the back was 2 RJ12 sockets, one went to the headset, one into the telephone. And a 3.5mm headphone socket that would connect to the iPod.

Telephone Conference Radio close up of the tape dispenser sockets that plug into the phone and the headset

Music Station Phone


I realized after a while that depending on the wiring, I could either make the music go directly into my headset, or I could feed it into the telephone system.

Then all I needed to do was make a conference line for people to call into, and we now have a live radio station broadcasting through the work telephone system.

Telephone Conference Radio close up of the tape roll with switch lever and dispenser
Telephone Conference Radio close up of the tape roll with switch lever

Circuit


This is one of my favorite circuit boards. Looking at the track lines and the quality, I think I would have made the circuit layout on the PC, taken into Photoshop and added the graphics and text, printed out onto transparency and laid on top of a printed circuit board with negative resit film, exposed it to light for 10-15min, then developed in solution, and finally used ferric chloride acid to etch away the unwanted copper. This is all from memory so might be wrong but that’s what I remember of the process.

Telephone Conference Radio circuit with prototype etched and printout of circuit

Mass Production


I wanted to go into ‘mass production’ of these. I gathered the part to make 100 units, however after testing on difference systems, soon realized the complexities of telephone headset systems (different wiring, impedance, etc).

This little project never made it to mass..

Telephone Conference Radio circuit with all components including tape dispenser and RJ12 sockets, and switches
Telephone Conference Radio circuit RJ12 sockets in a row
Telephone Conference Radio circuit with veroboard prototype and etched
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