bmp@bull.ecs.oz (Bruce Paterson) (05/03/90)
I have been investigating ways of implementing a custom slow speed (approx 100->200k) CSMA/CD network for an industrial application. It would be RS485 levels half duplex on twisted pairs. Whatever hardware is used needs to interface to a standard microprocessor in the field. It would also be nice if an off the shelf PC_AT board could be modified to be used on the same network. There are a number of options, but recently a Zilog Sales thingo mentioned that their SCC is used for appletalk, which apparently operates about 200k. My questions are: 1) Is appletalk a true CSMA/CD network, or does it use token passing or some such other software method ? 2) If it is CSMA/CD, what hardware does the collision & carrier detection ? Does the RX pin monitor the transmission for illegal transitions ? Which encoding is used ? 3) Anyone know the circuit ? 4) Are any PC boards available that can talk on appletalk ? Please mail replies if you can as I can't get to look at the mac groups very often. Thanks muchly, Bruce -- |Bruce Paterson ACSnet: bmp@cow.ecs.oz bmp@ecs.oz | |Electronics Engineer UUCP: ...seismo!munnari!bmp@cow.ecs.oz | |Email $companyname Just don't mention the word mattress ! |