See [Link: homeautomationnet.com] for the current rating of those devices (15 amps).

Each of the 16 housecodes (A through P) has 16 unit codes (1 through 16) for a total of 256 X-10 codes.

I have never used a IR 543 but I think Larry has a URL for a page that compares devices of this type in case you need to control more than 16 devices.

Cheers, Jim.