I have a sketch I have uploaded to my duemilanove that outputs rs232 commands to control and extron matrix switcher. I have connect up pins 0 & 1 to a ttl-rs232 shifter to make sure I am sending rs232 levels. When I connect the rs232 connection to my other computer using a keyspan rs232 to usb adapter I get the ascii command I need but when I connect it to the Extron switcher I get nothing. I have checked the serial commands, the cables and connections and all seems fine, it just doesn't seem to want to work.
I was wondering if because I have connected VCC of the shifter to 5v from the duemilanove that this might not be able to drive enough voltage to achieve correct rs232 levels, is this possible/likely or have I missed something else. Cheers for any advice you can offer. Steve