> I simply must know what it is that uses blocks of 8 x F88s. ;-) Is > it some kind of LED sign control? LEDs ? Oh, yawn ;-) No, it's a plug 'n' play PLC system. Not as dull as it sounds, each block is assigned a digital and/or analogue function(s). Not every F88 needs to be installed but its address range has to be reserved. Additionally, any F88 in the system has the capability of talking to any other. Although I've not implemented this, I've tested it and there are some intriguing possibilities, in the context of the application I'm sure this is just how CyberDyne Systems Corporation started ;-)) Hopefully I won't end up like Miles Bennett Dyson........... -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist