Re: X10 programming from PC

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

"Charles Sullivan" <cwsulliv@xxxxxxxxxxxx> wrote in message
news:pan.2006.09.14.04.14.23.615463@xxxxxxxxxxxxxxx
> On Tue, 12 Sep 2006 15:19:33 +0000, Geordie 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.
>>
>> TIA,
>> Geordie
>
> Are you sending the two bytes in one transmission?  Sending separately
> usually doesn't work.
>
> Try sending the single byte 0xEB and you should get the same byte echoed
> back.
>
>
Hi,

Thanks to all for your suggestions - as it happens, the immediate problem
lay elsewhere, but they're worth knowing about as I develop my code.

My starting point in all of this was that my X-10 system was getting
unreliable, and got worse when I upgraded the controlling PC to XP - I put
the problems down to the ActiveHome software, so decided to write my own.
After thinking about the posted suggestions, and trying a few other things
out, I tried out Test Communications on ActiveHome's Tools menu - no
response from the CM12.  Replaced the CM12 and everything works again!

That still leaves me disillusioned with the ActiveHome software - given that
the CM11/12 sends a checksum in response to each commend, why on earth
doesn't ActiveHome verify this and let the user know if there's a problem???
I'll continue with my own software, but without so much pressure!

Thanks again for the pointers,
Geordie