Re: Would This Work?

[nobody@xxxxxxxxxxxx (Dave Houston)]

No, I meant the TM751.

While they may have since changed things, X10 apparently used the same (or
nearly the same) firmware routines in both the TM751 and RR501 when I tested
this a few years back. Both use an SCR to toggle the relay and an SCR can
only be triggered during a positive half-cycle of the mains voltage. Relays
can only be assigned as units 1 or 9.

The relay is triggered before sending to the powerline so they need to wait
for a rising ZC signal to trigger the relay. This puts them 180°
out-of-phase with any transceiver on the opposite phase. For other unit
codes, they all transmit on the next ZC, regardless of polarity.

For the RR501, there have been a few different versions with different
capabilities. From about the time the CM11A was introduced, the RR501 has
had collision detection & automatic retransmit. This complicates things,
leading to duplicates of some commands but not others.

The Leviton all housecode version (HCPRF) also has collision detection and
automatic retransmit and can use any of 256 addresses for its relay but I
have not tested whether it cares about polarity.

All in all, the TM751 is easier to explain and to use in this way.

Some older transceivers with brown cases (model?) and some security base
stations apparently always waited for positive polarity so ignore everything
I've written if you have them. ;)

"JW" <jweb@xxxxxxxxxx> wrote:

>Dave,  I recognized the model you mentioned but after looking at my
>transceivers, the 751 doesn't have the unit codes, the RR501 does.  Did you
>mean 501, not 751?  Thanks,  Joe
>
>"Dave Houston" <nobody@xxxxxxxxxxxx> wrote in message
>news:4426ee65.187842015@xxxxxxxxxxxxxxxx
>> Two CM11As will coexist without problems.
>>
>> With two transceivers it depends on which transceivers. Two TM751s are OK
>> except for unit codes 1 & 9 if the transceivers are on opposite phases.
>>
>> "JW" <jweb@xxxxxxxxxx> wrote:
>>
>>>2 CM11s programmed the same in different parts of the house?  Or 2
>>>transceiver modules?  Thanks
>>>
>>
>