DTMF Decoder

Some time after I produced the MK1 repeater controller it started to become difficult to find OEM DTMF decoder boards for remote controlling repeaters at a sensible price. As a result I developed my DTMF1 PCB.

This is a very simple little board that takes AF in from a control receiver allowing up to 8 open collector outputs to be remotely controlled. The DTMF sequence sent to the board is in the form *XYZ where :

X = 1 to 4 configured by links LK1 and 2, no links fitted X=4, LK1 fitted X=3 etc.
Y = 1 to 8 - designating the open collector output number.
Z = 0 to 2 - 0 to set the output low, 1 to set it high and 2 to pulse low for 1 second.

Where this board is used for controlling an amateur repeater users are strongly advised not to use the repeater's receiver as the audio source for the DTMF1.

DTMF2 pcb overlay showing connection details

This board is available built and ready to use at £20.00.