Path: utzoo!attcan!utgpu!watmath!att!tut.cis.ohio-state.edu!network!ucsd!orion.cf.uci.edu!uci-ics!zardoz!conexch!ccicpg!cci632!rit!tropix!moscom!ur-valhalla!uhura.cc.rochester.edu!rochester!bbn!csd4.milw.wisc.edu!cs.utexas.edu!uunet!bywater!scifi!njs From: njs@scifi.UUCP (Nicholas J. Simicich) Newsgroups: comp.sys.ibm.pc.rt Subject: Re: Modem/Terminal Cables Message-ID: <634@scifi.UUCP> Date: 22 Jul 89 04:27:28 GMT References: <5026@umd5.umd.edu> Reply-To: njs@scifi.UUCP (Nicholas J. Simicich) Organization: Nick Simicich, Peekskill, NY Lines: 35 In article <5026@umd5.umd.edu> brett@umd5.umd.edu (Brett Bourbin) writes: >We are trying to add a modem ot one of our RTs and we don't have any of the >modem cables, P/N 6294794, but we have many terminal cables, P/N 6298186. >What I wanted to know was the differences between the two cables, i.e. the >pinouts, so I could modify the terminal one to be used on a modem. The terminal cable is a "null modem" cable. The modem cable carries the signal straight through. Depending on the signals you need to carry back to the RT, (what you are going to use it for, and how desperate you are) you might just be able to swap 2 and three on the 25 pin, and block all other signals. I don't recall offhand, but I think that the terminal cable is set up for "DTR pacing", and so an approximation is to swap DTR and DSR, and to presume that RTS and CTS are crossed with a loop back to CD. A few minutes with a test meter will confirm that, and tell you more than I can remember. The modem cable is straight through with the signals being TXD, RXD, CTS, RTS, DTR, DSR, RI, DCD, ground and ???. It should be represented on the 25 pin side, anyway. The printer cable is also a "null modem" cable, but with different signals crossed. >I looked at the Tech manuals and could not find this information, so any >help you can give would help greatly. Look in the RT planning giude. Cable layouts are in there. Another place you could look is in the RT hardware technical reference manual. Did you look under the four port adapter? I don't have my manual in front of me (I'm at home) but I thout it was there. The four port cards and the planar ports use the same cables. (.....) -- Nick Simicich --- uunet!bywater!scifi!njs --- njs@ibm.com (Internet)