How can I connect a Motorola TDN8310A to my ICOM?

[rlgoodin]

I'm trying to connect my MotorolaTDN8310A DTMF Microphone to an Icom IC2100H. Here is the pinout of the Radio:

1 - +8VDC
2 - MU/D an up down switch of no concern.
3 - M8VSW also of no value to me
4 - PTT
5 - MICe the mic ground
6 - MIC
7 - GND
8 - MDATA not of any concern to me either

Here is the pinout of the Mic:

1 - Mic Hi (RED)
2 - Monitor (White)
3 - Mic Lo (Black)
4 - PTT Lo (Blue)
5 - PTT (Green)
6 - SW B+ (probably my Yellow/White)

I hope this will not be difficult.

Thanx
Lee - N7MFY

[N4UMJ]

Check out this guys website.

http://www.dapcom.com/mobileradios.htm

He has hooked a Motorola Maxtrac Mic to his IC706MKIIG which may be very similar.

I always wanted to try that on my Icoms here.

Eddie
N4UMJ

[bernie]

My two bits worth:
The only real problem is that the Motorola mike has an amplifer, thus requires power to operate. It behaves just like a carbon telephone mike.
It is known as an analog carbon mike.
A simple circuit to provide the bias is:

You need a .1 uf cap, as well as a 560 ohm resistor. 1/8 W or so.
connect the 8V line to the mike hi line, mike high to mike input of the radio with the .1 uf cap in series. This may be omitted if the radio is already "DC blocked". Mike lo to ground. You can figure out the others.
If there is noise on the TX audio you may need to filter the 8V line with a 10Uf cap to ground.
Aloha, Bernie.