As to the CM19A, if it was as good as the CM15A, why does X10 include a TM751 transceiver with it?
Dan -
It is my understanding that X10.com started selling a cheaper "stripped down" package, that included the CM19A instead of the CM15A.
From what I understand (I may have my facts wrong, though - someone please correct me if I'm wrong), the CM15A transmits and receives both RF and PLC, and has on-board memory for stand-alone running of timers and *certain types of* macros.
The CM19A is an RF-only transceiver, which connects to the PC via USB. They need to include the TM751 so that there is a way to get those RF commands into the powerline.
I am guessing that they included the TM751 instead of the RR501 because: (a) it is cheaper, and (b) they probably have a warehouse full of them they want to get rid of.
However, with that package, there is no way to get PLC commands (from wired remotes, or two-way switches, for example) back into the AHP software.