Re: X10 programming from PC

["Geordie" <bill-gibson_remove_@xxxxxxxxxxxxx>]

"Robert Bonomi" <bonomi@xxxxxxxxxxxxxxxxxxxx> wrote in message
news:12ge6c6gkvh4d@xxxxxxxxxxxxxxxxxxxxx
> In article <9eANg.27133$DB3.23003@xxxxxxxxxxxxxxxxxxxx>,
> Geordie <bill-gibson_remove_@xxxxxxxxxxxxx> wrote:
>>Hi,
>>
>>I'm trying to control an X10 system through a CM12U (similar to CM11) via
>>the serial port, using my own software.
>>
>>I know the software is correctly talking to the serial port (because I
>>tried
>>it 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't
>>get 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 all
>>transmissions between the PC and the interface with the difference being
>>in
>>the first transmission from the PC." - but I couldn't find anything about
>>__what__ is different about the first transmission.
>
> The first possibility that comes to mind is that the CM12 might be DTE,
> not DCE, and your cabling is wrong.
>>
>
> Try adding a null-modem.

Hi Robert,
Thanks for responding.  I know from bitter experience that transposing DTE
and DCE can be a PITA to resolve, but I don't believe that's the problem -
my software communicates with a modem ok and, though I didn't mention it,
the CM12 responds to the ActiveHome software on the same port/cable.
Regards,
Geordie