So, I've been experimenting a bit with a SmartHome LampLinc (2000SHL) module I got on ebay to try and learn more about the nitty-gritty of X10 dimming commands, and its behavior is a bit surprising.
This module responds to the "preset dim" command as detailed in technicalnote.pdf, but curiously, this only accesses the first 32 of apparently 33 dim levels (as read by my old Radio Cack multimeter), with the 33rd level only settable with the "on" command. The regular "dim" and "bright" commands seem to go down or up by one of the 33 dim levels when sent in double form or in single (non-repeated) form. When sent a dim or bright command in triple, though, it appears to go down or up by approximately 3½ of the 33 dim levels; in quadruple, 6½, in quintuple, 9.
In sum, it seems that individual dim/brights are measured on the 33-point scale, but repeated dim/brights are measured on a scale of about 13 points from fully off to fully on. This is quite different from the 22-point scale assumed by the CM11A interface. Maybe that's because the LampLinc module is made by SmartHome and not X-10 themselves? I don't have any X-10 lamp modules to test with to see if they do the same thing, at least not yet, but I'm curious now to see if they hold to the 22-point scale defined by the CM11A.
Anyway, just thought this was interesting. I might have to change how I represent dimming in
pyx10 depending on what I find out...