Re: TM12 question ?

[Kevin Hawkins <tivo@xxxxxxx>]

Title: Re: [ukha_d] TM12 question ?

The official line I believe is don't do this, however I would be tempted to
try it - but there are three issues that could cause problems. Non I
believe would cause damage to any modules though. There may be a reason for
this official don't - see i) below.

   1) The TM12 has an inbuilt appliance module. This has a
hardcoded address and so you will end up with two modules on this address
(not in itself a problem). However these appliance modules do support
active monitoring ie  you can interrogate them remotely to query their
status. If you have two or more TM12's on the same housecode the 'status'
result would be unpredicatable as their responses would clash or
conflict.

   If you are 'in range' of more than 1 TM12 then two other
problems occur. i) or ii) will get you one way or the other. You may be
able to live with ii)

   i) Several TM12's may receive the same rf signals and as
such they will all put their X10 data on the mains. This may well cause
collisions (I don't know how adept the circuitry is in a TM12 for avoiding
this). The effect of collisions is that the data can get lost or scrambled.
This means that the unit you are addressing may not see the data or
possibly worse still the data might get corrupted and cause another
unexpected device to respond. X10 is not a resilient or well error checked
protocol. If the TM12's have no collision detection built in then almost
certainly they won't work and this may be why the official line is don't do
it. anyone know for definate ?

   ii) If collisions are not a problem then data my well get
sent  from each TM12 that is in range causing duplication of the
commands. This is undesireable and in more complex 'macro' type scenarios
it could be really problematic. In practice for ON / OFF control it should
not pose too many problems however it will cause problems for dim and
bright commands as they work by repeating a command several times to change
the level of the light, this will get messed up and result in unpredictable
results.
   
   I don't think you will do any harm to anything but it
just may not work the way you want it to. For wall mounted RF switches you
would be better siting them to communicate with just one TM12 on perhaps a
different housecode. You could transpose the addressed units back with any
software or hardware that supports macros. The housewide operation of a
keyfob is more difficult to achieve though.

   In the States there are two solutions I have seen for
this. They have an RF repeater available that simple receives the RF signal
and transmits (boosts / relays) it again. I do not know of a CE approved
model. I have also seen a mod published for an RF remote that caused it to
send the commands out on two different housecodes, say first on A then B.
You could then set your receivers up on separate housecodes and transpose
one housecode if needed using a macro (but only if the other corresponding
one was not received). 


   Kevin

on 4/5/01 9:01 pm, geraint@xxxxxxx wrote:

> Hi all,
>
> Thinking about putting in some RF-X10 kit...
>
> question....I noticed that the range I could experience would be 
> about 10metres through walls.
> Could I in theory add more TM12's on the SAME housecode to give an 
> extended range,,,i.e a couple upstairs at either end of the house, 
> and likewise downstairs.
>
> I want to use the SS13 stick on wall switch's in places where mains 
> feeds are going to be a pain, so this would be a perfect solution for 
> me, but as I said,,,can it go on the same code.
>
> It also lets me use the remote keyfob for external lighting and 
> garage door motor.
>
> I won't be using the appliance side of it on code 1, so I know I 
> won't have 4 or 5 appliances switching on that housecode at the same 
> time.
>
> any ideas ?
>
> regards
>
> Geraint Williams
> Award Computing Ltd
>
>
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