I have been working on a project with the serial port, OPL and a GPS unit. So far I can read through the serial port in OPL from a PC using hyper terminal but not from the GPS unit. I have been using a null modem cable and it does work with a psion 5 and the GPS. Its not software, or cables so it has to be hardware. Can anybody pleeeeeeeease shed any light on why this will not work. Maybe data signals too weak? 
Help with serial port again...please
Hiya
I don't really know why it wont work, this being a complete stab in the dark but....
When i was moving from a Revo to the 9210 i was told/read somewhere that the files werent compatible because the revo uses a different character set to the 9210, the 9210 being ascii and the revo being proprietry.... Now im not sure of this 100% but it sounds logical, but whatever it is, the software may be sending different control characters if its a mod of your old software....
As i said, just a stab in the dark, but might point you in the right direction.
Stephen