Build Your Own SLA/SLS

I am trying to connect to the Acer P1500 via RS232, and I cannot figure out how.
I tried to connect via an USB to Serial adapter I once ordered in China, and a Nullmodem Cable.
I cannot connect, but I am not sure where the problem is, as it could eiter be in CW, an issue with the converter or a wrong wiring in the nullmodem cable (as there are a lot of different types).

So how did you guys connect to projectors?
Is it right to use a nullmodem cable?
Can anyone recommend me a hardware setup?
Or can anyone tell me how to test my current setup to identify the problem?

Somehow there is no documentation about this at all in the Acer Manual, and I did not succeed finding information trough google, as RS232 seems to be a very difficult standart.

Can you try it without the null modem cable? I haven't needed to use one on most things I've talked to via RS232, but I've never tried a projector.

I can't help other than suggesting a look through avsforum.com. Lots of A/V gurus there and I bet a few actually use the rs232 of projectors when configuring home theaters.

@Scatterplot: I tried to make my own cable , this maybe complicates the issue a bit... I was looking for nullmodem wiring because ther is a male D9 connector at the projector...
@orangezero: Thanks, for the tip, but I did not find anything there...
@Dr. Woo: Thank you for your troubleshooting guide, unfortunately I tried all these things before posting to the forum Does your serial converter have a male connector too? And so you are using a female to female cable?

I ordered a proper null modem cable and a Profilic Chipset USB - Serial Convertor, and it works now For testing the serial command I'd suggest Termite, as more popular Putty caused issues.

In CW I lost some time, because I did not select to which Display I want to send the command, so that was my little trap there.