Count up the bits in the UPB command sequence and you'll see that UPB can place any command onto the powerline in about .25 - .50 seconds. 4800 baud is based on a 60hz sine wave at esentially 4 unique values (2 bits) per zero crossing. UPB does this by placing specifically timed pulses in one of two parts of the sine wave at about the 50V level allowing it to form 01,00,10 and 11 twice per full AC cycle. That times 60 gives you the advertised rate. UPB response time is about 50% faster than X10 btw and the 50Volt signal level gives it its resiliancy to signal attenuation.Dean Roddey said:The interface device (PIM) runs at 4800 baud???? What's up with that kind of cave-speed on something that's supposed to be the latest and greatest powerline protocol?
When I first read the spec, I worried about this as well. As it turns out, 4800 baud is the slowest baud-rate that allows the serial stream to keep up with worst-case traffic on the power-line. So, although the serial-port bandwidth utilization may approach 100% at 4800 baud, it should not need to exceed 100%.Dean Roddey said:That's going to be a very small straw to try to suck much two way feedback through.