Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!watmath!clyde!rutgers!lll-lcc!ptsfa!ihnp4!mb2c!fmsrl7!wayne From: wayne@fmsrl7.UUCP Newsgroups: comp.dcom.modems,comp.periphs,misc.wanted Subject: Re: Reliability of Modular Jacks Message-ID: <796@fmsrl7.UUCP> Date: Wed, 11-Feb-87 11:42:56 EST Article-I.D.: fmsrl7.796 Posted: Wed Feb 11 11:42:56 1987 Date-Received: Fri, 13-Feb-87 21:36:44 EST References: <267@aucs.UUCP> <299@mtxinu.UUCP> Reply-To: wayne@fmsrl7.UUCP (Michael R. Wayne) Distribution: na Organization: Ford Motor Company, Scientific Research Labs, Dearborn, MI Lines: 75 Keywords: RJ-11, RJ-12, RJ-45, RS-232 Summary: Suggested method for wiring Xref: watmath comp.dcom.modems:209 comp.periphs:201 misc.wanted:513 In article <299@mtxinu.UUCP> ed@mtxinu.UUCP (Ed Gould) writes: >>Most of the terminals on our campus are presently connected to the wall >>with four-prong plugs. We are considering wiring new terminals with >>either four-wire or six-wire modular jacks. If anyone has had bad >>experiences with these connectors I'd appreciate hearing your warnings. > >I offer two cautions, however. First, modular connectors are not very >robust mechanically - they don't stand up well to repeated >insertion/removal cycles. Second, there is no standard way in which >they're wired, so care in desigining the system is needed. In the department I do work for here at Ford, we are using RJ-45 connectors (8 line modular) for our serial communications. Here is the wiring layout: Revised RJ45 standard (Version 1R5 09/24/86) Black RJ45 DB Gray RJ45 RJ 11 RJ 12 RJ 45 DTE DCE 25 DCE DTE I/O Name ----- ----- ----- ------ ------ -- ------ ------ --- ----------------- 1 Blue Gray 5 Blue Orange IN - Remote receive OK 1 2 Orange Brown 8 Brown Gray IN - Remote device up 1 2 3 Black Yellow 3 Green Red IN - Data in 2 3 4 Red Green 7 Yellow Black - Ground 3 4 5 Green Red 7 Black Yellow - Ground 4 5 6 Yellow Black 2 Red Green OUT - Data out 6 7 Brown Orange 20 Gray Brown OUT - Local device up 8 Gray Blue 4 Orange Blue OUT - Local recieve OK You may ignore the color codes, these are for RJ-45/RS232 connectors purchased from Black Box (412) 746-5530 $9.95@. Reasoning behind this layout: 1) Using crossed wiring, ANY two devices may be connected. Snap a cable between 2 terminals and they talk, no need to locate a null modem cable. Note that we do not use "straight through" cables (what most people recommend for computers). If you have spent as many hours fighting RS232 "standard connections" as I have, you will appreciate the joy inherent in this. 2) If all you need is TD, RD and ground, all you need is 4 line cable (RJ-11). Cheap, cheap :-) 3) If you need only TD, RD and devices available, you can use 6 line cable (RJ-12). Inexpensive. 4) If you need hardware handshaking, 8 line cable (RJ-45) will do it all. 5) The DB25 connections above are advisory, not absolute. The connector is responsible for having the appropriate signals on the correct RJ lines. Bolt the things on so they become part of the device. 6) Black Box also sells DB-9/BJ45 connectors so we can make PCs conform as well. The time savings in using this system is enormous. The only waste is the 2 ground lines in the center. We have been using this for some time with no problems (the latest revision was for color codes, Black Box changed the order of the colors). If you have any questions, feel free to mail or call me. For all the people who worry about ignorant people coming around and connecting our data lines to the phone company: - We generally keep everything plugged in so there are no open lines or ports to use. - With the number of cables we have, even the telephone repair men are intimidated. - We try to restrict access to authorized people. - If you are going to use wall jacks, I suggest that you label them so that people know better than to plug their phone in. -- ===== Your life is your own fault! ============== Rebel or be oppressed! ===== Michael R. Wayne (313) 322-3986 UUCP: {epsilon|ihnp4}!mb2c!fmsrl7!wayne Working at (but not employed by) Ford Motor Company ** This space for rent ** Since I am an independent consultant, the above opinions ARE my employers. ===== Are your moral/ethical/religious/political beliefs really rational? ====