Rotary dial CW key

by OH6DC

Rotary dial telephones are no longer at the cutting edge of telecommunication technology. Fortunately you can easily update them to rotary telegraph keys. Follow these instructions:

Open the phone carefully and inspect what it has eaten.

In this backside picture of the rotary dial you can see the contacts for dialing pulses (rear) and contacts which operate whenever the dial wheel is away from its rest position (front). We use the latter ones in this project.

Only few wiring modifications are needed in this L.M.Ericsson Dialog phone: move the red wire from screw 15 to 5 and replace the telephone plug with a 6.3mm plug (red and black wires are used in keying, cut the yellow one).

There are three different CW sending speeds available. Use these dial numbers:

slow speed: dots "3", dashes "9"

medium speed: dots "2", dashes "6"

fast speed: dots "1", dashes "3"

Confused? Take a look at this video to find out how the key is used at different speeds.