ICOM 706 DTMF
 

I have an ICOM 706 MKIIG. I know there is a DTMF mic yet I have the
Heil mic that uses the RJ45 connector.

I saw a web page detailing how to connect a DTMF box to the rear of
the radio via a radio shack DTMF generator. That generator does not
seem to be available now. Has anyone built a box from something
else. I was even thinking about an old phone...

Keith, N3HGN

I saw a web page detailing how to connect a DTMF box to the rear of
the radio via a radio shack DTMF generator. That generator does not
seem to be available now. Has anyone built a box from something
else. I was even thinking about an old phone..

Keith-

The touchtone pad in an old telephone has numerous wires connecting into the
guts of the phone. Perhaps an old ARRL handbook or FM & Repeaters Handbook
would have information about how to hook one up, but there may be a simpler
way.

Just connect the two leads out of the phone through a series resistor (maybe
620 Ohms?), to a DC power source. The phone company used 48 volt batteries,
but it will probably work with as little as a 9 volt transistor battery.

Connect a series capacitor from the junction of the resistor and the phone, to
a potentiometer, and the output of the potentiometer to your audio input.

When the phone is on-hook, the phone line is disconnected, so you might want to
bypass the hook switch. When off-hook, the phone's earphone and microphone are
connected, so you may want to disconnect them.

Good luck!

73, Fred, K4DII

I saw a web page detailing how to connect a DTMF box to the rear of
the radio via a radio shack DTMF generator. That generator does not
seem to be available now. Has anyone built a box from something
else. I was even thinking about an old phone..

Keith-

The touchtone pad in an old telephone has numerous wires connecting into the
guts of the phone. Perhaps an old ARRL handbook or FM & Repeaters Handbook
would have information about how to hook one up, but there may be a simpler
way.

Just connect the two leads out of the phone through a series resistor (maybe
620 Ohms?), to a DC power source. The phone company used 48 volt batteries,
but it will probably work with as little as a 9 volt transistor battery.

Connect a series capacitor from the junction of the resistor and the phone, to
a potentiometer, and the output of the potentiometer to your audio input.

When the phone is on-hook, the phone line is disconnected, so you might want to
bypass the hook switch. When off-hook, the phone's earphone and microphone are
connected, so you may want to disconnect them.

Good luck!

73, Fred, K4DII

I saw a web page detailing how to connect a DTMF box to the rear of
the radio via a radio shack DTMF generator. That generator does not
seem to be available now. Has anyone built a box from something
else. I was even thinking about an old phone..

Keith-

The touchtone pad in an old telephone has numerous wires connecting into the
guts of the phone. Perhaps an old ARRL handbook or FM & Repeaters Handbook
would have information about how to hook one up, but there may be a simpler
way.

Just connect the two leads out of the phone through a series resistor (maybe
620 Ohms?), to a DC power source. The phone company used 48 volt batteries,
but it will probably work with as little as a 9 volt transistor battery.

Connect a series capacitor from the junction of the resistor and the phone, to
a potentiometer, and the output of the potentiometer to your audio input.

When the phone is on-hook, the phone line is disconnected, so you might want to
bypass the hook switch. When off-hook, the phone's earphone and microphone are
connected, so you may want to disconnect them.

Good luck!

73, Fred, K4DII