> Close. 10/100mbps Ethernet uses wires 1,2,3,6 but that is pair 2 & 3. > Pair > one is the pair up the dead center (pins 4&5), pair 2 is pins 1&2, pair 3 > is > 3&6 and pair 4 is 7&8. A T1 uses pairs 1&2, which is why you can't use a > regular crossover cable for a T1 crossover, but you can use a regular > ethernet patch cable as a T1 patch cable.
Correct. I mixed up "pair 1" with "the pair of wires connected to pins 1 and 2." T1 uses "Pair 1" and "Pair 2," which was what I was trying to say and what you *did* say! :) > > An RJ45 carrying a T1 is: > > 1 - RxA > > 2 - RxB > > 4 - TxA > > 5 - TxB > If you are referring to A and B as the differential signal components then you're right about the wiring. In either case you're wrong with respect to the pairing. :-) Sorry, I am used to the way NEC documents their PBXs and this is what they call it. The Zytrax website documents it like this: Pin: Signal: 1 Rx1 2 Rx2 4 Tx1 5 Tx2 (http://www.zytrax.com/tech/layer_1/cables/tech_rs232.htm - bottom of page) So my question about a "real" T1 cable isn't specifically about a crossover cable, although the principle will still apply. I was talking about using Cat5/5e 4-pair cable (*not* a pre-made Ethernet patch cable, just Cat5 cable in general) to carry a T1 signal between the NIU/SmartJack to the CPE. (I could crimp my own or buy them, depending upon my specific needs. For a short jump I'd probably just fabricate my own.) So the question is really this: which pairs need to be twisted together in a "real" T1 patch cable? Since the two receive wires are on pair 2, and the two transmit wires are on pair 1, it *seems* logical enough to say that Rx1 and Rx2 should be on the same twisted pair, ditto for Tx1 and Tx2. Is that correct? -MC _______________________________________________ --Bandwidth and Colocation provided by Easynews.com -- Asterisk-Users mailing list To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users
