Often this is accomplished with RS485 multidrop networks. These are usually in some kind of master-slave protocol, with the master polling the slaves for a response. The slaves don't have access to the RS-485 bus unless sent an addressed message by the master. There are RS485-RS232 converters out there. I use a couple of temperature control systems that work this way. I think I2C also can work this way, although I don't understand it as well. If you are designing both ends of the system this might suit your needs. If your peripheral devices are already set in stone as RS-232, then it won't help you much. Lawrence Lile P.S. RS-232 is a protocol originally named after Radio Shack: the guy who invented the protocol went down to Radio Shack and bought $2.32 worth of parts and voila'! he had an RS-232 converter! ;-) ----- Original Message ----- From: "MILTON MEDICINTEKNIK KB" To: Sent: Wednesday, April 11, 2001 3:12 PM Subject: [EE] A five-to-one RS 232 - cruncher - anyone ? Hello, A question: 5 different devices use RS 232 as a communication protocol to/from a controller (or PC). I need to combine those lines to ONE RS 232 line. One way to do it is to use 3 PIC's with dual ports (or 6 single port PIC's) or makbe "bit-bang" data, make up a que, and let one port become the "compressed" data stream further down the line. however... O have tried to find a commerciallay available box that is doing this magic tric - and almost suceeded. I don't have time to design the thing, and wonder if anyone out there know where I can buy one :=) NOTE: It must be a separate box. A multiple RS 232 comm card to a PC doesn't count. Any hint appreciated. Thank you. Sven in Sweden -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads