Alexander,
The suggestion of one master talking to the PC is not to lessen the burden for the PC, if this was a 'burden' for a PC we would all be in trouble. T have found that the way the PC's are wired makes it very difficult to set up multislave communications, the PC is just not supposed to do so. DO NOT monitor collision, make a protocol (slaves speak only when spoken to) that makes collision impossible. collision detection is 777 times more complicated than collision avoidance. The 'standard' checksumming for serial transfers in non-lifethreatening situations id to add all bytes (throw away overflow) and put the complement at the end, then the reading port should sum all bytes and get a zero sum.
Pilgrim, what an appropiate handle this time of year - happy turkey day
Erik Malund