My point is that multiple transmitters on an RS-232 link aren't likely to work well because the protocol is point to point, and there is no "collision recovery" protocol. This isn't an Ethernet cable. It's RS-232. Point to point, not multipoint.
Even if spec-compliant end point electronics aren't damaged by such a connection, a receiver is likely to be confused by the competing efforts of multiple transmitters. One of the transmitters will be attempting to hold the TxD line at mark, the other at space. Which one wins depends on the implementation. Dick, K6KR -----Original Message----- From: Elecraft [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Lynn W. Taylor, WB6UUT Sent: Monday, September 15, 2014 8:15 AM To: elecraft@mailman.qth.net Subject: Re: [Elecraft] [acom-list] Re: Elecraft K3 and ACOM 2000A There is the formal standard, and there is the defacto standard. The formal standard says +3v for 1, -3v for 0, and that less than 3v is undefined. The common driver chips (1488 and 1489) worked just fine with TTL levels -- 5v being above +3, and 0v being close enough to -3v. I've never seen anything that required -3v for logic zero. -- Lynn On 9/15/2014 6:59 AM, Don Wilhelm wrote: > David, > > That is true the specification says that condition will not cause > damage to compliant drivers and receivers, but if two drivers are > placed on an RS-232 signal line, they will *not* work together and > will result in corrupt data (assuming they are on the TXD or RXD > signal lines). > > You are correct that damage may occur to non-compliant (but > compatible) drivers and receivers. The PC serial cards, USB to serial > adapters, and most ham gear do not implement compliant RS-232 interfaces. > > 73, > Don W3FPR ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to d...@elecraft.com ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
