Carlos, I'd be interested in that circuit. Thanks. Vic Lopez -----Original Message----- From: Carlos L. M. To: PICLIST@MITVMA.MIT.EDU Date: Friday, May 28, 1999 9:09 AM Subject: Re: PIC & RS485 >PICLIST@MITVMA.MIT.EDU wrote: > >> Hello all: >> >> For the next phase of my PIC project (home security), I want to have remote >> keypads communicating (only) with the master control unit. I originally >> wanted to use RS232, but was under the impression that RS232 is difficult >> to deal with when using long runs (i.e. through a house) and multiple >> interface nodes. For future expandability of the "network", I am leaning >> toward RS485, using a Maxim interface chip. However, I will not run it as >> a multi-drop configuration, but as a star-type configuration, with the >> keypads running (throughout the house) directly to the master. >> >> My question is: is my impression of RS232 unfounded? If so, why? Has >> anyone used RS485 in the way I want to use it? If so, did you use a >> terminating resistor as each node to minimize reflections? Any other >> information you could provide would be very helpful >> >> Regards, >> >> --John > >You can use the RS232 for long distance but you have to make an amplifier to >use it without problems. I saw one circit sometime, that could use the RS232 in >a ddistance of 100m from the computer. Maybe, if you are intereted in this >circuit, I can search it and send you. > >Carlos L.M. > >