Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!accuvax.nwu.edu!nucsrl!telecom-request From: "John R. Levine" Newsgroups: comp.dcom.telecom Subject: Re: Question on Telephone Jacks Message-ID: <3763@accuvax.nwu.edu> Date: 11 Feb 90 19:36:39 GMT Sender: news@accuvax.nwu.edu Organization: Segue Software, Cambridge MA Lines: 23 Approved: Telecom@eecs.nwu.edu X-Submissions-To: telecom@eecs.nwu.edu X-Administrivia-To: telecom-request@eecs.nwu.edu X-Telecom-Digest: Volume 10, Issue 94, message 4 of 6 In article <3732@accuvax.nwu.edu> you write: >I'm wondering what is unique about an RJ-41S termination other than >the fact that it seems to be used for data terminal equipment like modems? The RJ-41S is a general purpose data jack. It contains three different things: the first is the regular tip and ring, the second is a FLL pad that provides a signal suitable for equipment expecting a fixed loss loop, the third is a programming resistor (chosen at installation time) for equipment that has an internal FLL pad. (Note that this "pad" is unrelated to an X.25 PAD, I don't know what it stands for in this case.) An RJ-41S jack has a switch to flip between regular tip/ring and FLL tip/ring. Your RJ-41S equipment probably depends on the FLL pad so if all you have is an RJ-11, you're out of luck. If it just needed the programming resistor, it could use the simpler RJ-45S jack with the resistor but no pad. Regards, John Levine, johnl@esegue.segue.boston.ma.us, {spdcc|ima|lotus}!esegue!johnl