When is an RS-232 port not an RS-232 port (ACOM 600S RS-232 Mod)

I have been attempting to get the remote power on capability of ACOM Director Plus working with the ACOM 600S however no matter what I tried I was unable to make it work. I tried swapping to a null modem cable and amazingly the remote power on worked perfectly, however I could no longer connect to the amp from the computer.

On closer inspection of the manual, it would appear that there is something unusual about the wiring for the RS-232 port

At first glance everything seems fine, however pins 2 & 3 (TxD and RxD) are wired to use a straight through RS-232 cable, but pins 6 & 8 (DSR and CTS used for remote power on) are wired to use a null modem cable. This means that for full control of the amp a custom cable must be used.

What peaked my interest is the fact that pins 4 & 7 are noted as Not Connected, these are the DTR and RTS lines and are what’s used to tell the amp to power on. In order for this to work they must be connected to pins 6 and 8. It occured to me that it should be possible to make a modification to the amp to enable it to support a regular straight through RS-232 cable.

To that end i’ve put together a mod which can be found over at ACOM 600S RS-232 RPON Mod which details how to do this. It’s only useful if you intend to use the RPON capability through the RS-232 port, however it will avoid the need for custom cables and is still backward compatible should a custom cable happen to be used in the future.

IMPORTANT – YOU SHOULD NOT ATTEMPT THIS MODIFICATION UNLESS YOU ARE CERTAIN YOU HAVE THE SKILLS AND EQUIPMENT REQUIRED, YOU COULD DAMAGE YOUR AMPLIFIER. THIS MODIFICATION IS NOT ENDORSED BY ACOM. NO RESPONSIBILITY IS TAKEN BY M0YOM, ACOM OR ANYONE ELSE FOR ANY DAMAGE OR INJURY THAT MAY RESULT FROM PERFORMING THIS MODIFICATION. PERFORMING THIS MODIFICATION WILL LIKELY VOID YOUR WARRANTY.

 

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M0YOM

M0YOM

I'm James, a radio amateur, software engineer and professional geek. I'm the IT Director for a software company and Director and part owner of a web design, hosting and media business.

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