I have my Acom hooked to my new SS2DX with the cable built up by Billy, GM6DX. The EXT CTRL TX and RX matrix is populated per the documentation and the Acom is set to BCD mode. By all accounts, this should work but it does not. Acom gives a CAT ERROR.

so this morning I put a breakout in the cable from radio to amp so I can monitor voltage levels.

I find that the signals showing up at the Acom end show correct BCD coding or at least coding is same as in the EXT CTRL matrix.

The interesting thing I find is that voltage levels seem strange, .37 vdc for LOW and .57 for HIGH. this is consistent for all bands and all signals.

Acom manual indicates that this input is TTL level. These voltage levels do not appear appropriate for a device expecting TTL level signals.

In any event , the amp gives a CAT ERROR so something must not be correct. Suggestions are appreciated.

Jim
N1NK

Is anyone using the GM6DX cable and a solid state Acom amp? Acom 700s, 1200s, etc?

Hi Jim.
I have not the setup as you , I use the rs232 connection to acom 700 . and SDC software .
But I have used the ext controls for many other things .. I looks like you dont have the pull up resistors .. the ext control is a open collector , so it needs a resistor to 5v . to preform the ttl level.. just a guess

73 gl de Brian

I have the GM6DX cable which supposedly has the pull up resistors. but I will double check. easy to do as I have DB15HD breakout boards so I can plug the cable end onto the board and measure what is present at pins or between pins. it also appears that the 13.8 vdc signal on pin 14 is missing. this may be the real problem.
how does the method you use work?
N1NK

Hi Jim .
It works fine , the band select goes via TCI in the SDC software .
The PTT must go via Ext control .
I use a seriel to USB adapter , and homemade cable.. between adapter and ACOM ..

I have sdr2pro so the drive power give med 500-600 watts ,

73 de Brian