Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!uwm.edu!cs.utexas.edu!usc!bbn!news From: news@bbn.COM (News system owner ID) Newsgroups: comp.dcom.modems Subject: Re: New "Alternate Connector For Use With ANSI/EIA-232-D" Message-ID: <45725@bbn.COM> Date: 18 Sep 89 16:30:10 GMT References: <870.251007A2@zswamp.fidonet.org> <328@gp.govt.nz> <8539@hoptoad.uucp> Reply-To: pplaceway@izar.bbn.com (Paul W. Placeway) Organization: Bolt Beranek and Newman Inc., Cambridge MA Lines: 56 John Gilmore writes: < The standards bogons are at it again. At least the ISO hasn't gotten involved yet (yea, 100 conductor serial cables, what a GOOD idea! :-) ) < Draft goal spec of new connector: < ... < < Draft signal spec: < < [1] GND < [2] TX Data < [3] RX Data < [4] I'm Here (DTR) < [5] You're Here (DSR/CD) < [6] TX Clock (synchronous modems and flow control) < [7] RX Clock (synchronous modems and flow control) < [8] +5V, fused and current-limited < ... < There should be no male/female connectors; any connector should < fit into any other one. Ideally you could plug it in with a 180 degree < rotation to cross the lines (I'm Here <-> You're Here and etc). That way < you can not only plug two devices together with a single cable, but you < can also extend the length by plugging N cables together... True wisdom. Let's see. Number them like I did, then make a connector that has something like this (from the perspective of the TX device 2 1 6 4 8 (TX side) (8) 5 7 1 3 (RX (inverted) side) Where the (8) is either used as a +5 load, or is not connected. Note that the grounds and +5s run next to the transmit and recieve, to help noise shield things. A suggestion: The TX side should be female, the RX side male. This looses the ability to flip and play, but wins in that there is no possible way to hook it up wrong. I say female for TX so that there is less change of shorting the +5 output by abusing pins. In general, I like the mechanicals of the squeezed SCSI and SMD cables; perhaps something like them, only not D shaped but rectangular instead, and with clips and receptors on both sides, in some manner or other. One thing I would add is that the data rates must be capable of up to at least 1.2 Mbps, maybe more, to be really useful for a number of years to come (V.32 is, after all, 1/4 of the max. real RS323 speed (actually, that's debatable). -- Paul Placeway ,