X10 programming from PC

Geordie · 2006-09-12T15:19:33+00:00

Hi,I'm trying to control an X10 system through a CM12U (similar to CM11) viathe serial port, using my own software.I know the software is correctly talking to the serial port (because I triedit with a modem), but I'm having difficulty communicating with the CM12.What I'm sending is 0x04 (Header) then 0x5E (to address unit G2) but I can'tget a Checksum back from the CM12.Any thoughts? One thing I noticed in the "Interface Communication Protocol"document at the end of section 3.1 is "This format is typical of alltransmissions between the PC and the interface with the difference being inthe first transmission from the PC." - but I couldn't find anything about__what__ is different about the first transmission.TIA,Geordie