atcomsystems.ca/forum Forums Wiring - Telecom Carriers - Trunks & Services T1's, CSU's and DSU's What is the proper wire squence from smart jack to 66 to keystone jack?

I had a strong tone from the 66 punc down to the keystone jack so that eliminated any cut in the wiring. dsy/csu card in router in alarm mode. The smart jack is red in alarm. Used a loop back to test smart jack alarm light went green. Loop back test of keystone jack at wall plate smartjack was red in alarm. cat5 cable white/blue , blue,white and white orange,orange white match same pair colors on cat5 horizontal cable. But on jeystone jack the pairs colors matched with termination points on keystone jack following the 568B standard. I need to know, what pair NUMBER at the jack port number on Smart Jack is the correct pair? I could NOT get the smart jack out of alarm no matter what wire combination. I tried. Thanks

pinout is 1&2, 4&5 for a T1
T&R, T1&R1

https://arcelect.com/RJ48C_and_RJ48S_8_position_jack_.htm

Fyi, strong tone doesnt eliminate possibility of an open unless you can short the pair to cancel the tone out

Also strong tone doesn't indicate a proper wire mapping.

Please refer to my response to your other post on this subject.

Do a continuity test on the pins 1,2,4 and 5 from the jack to the 66 block using your toner. You might have an open on one of the pairs.

I'm not sure if I made myself clear in my other posts. If this circuit is truly a T1 as you mentioned, which is for Local area data channels/subrate digital services, you should have your signal on pins 1, 2, 7 and 8 straight through.

Only a true 1.544 Mbps digital services circuit, such as a PRI, uses pins 1, 2, 4 and 5. Are you sure that this isn't your problem?

Should you be using the white/brown pair and not the white/blue pair? I know it's easy to refer to any circuit as a "T1", just like the way people use "RJ45" for any 8P8C plug/jack. Is it really a regular T1?

Ed, since it is on a "Smart Jack", it it 99% going to be on 1&2 and 4&5. Since OP has a loopback plug that turns the light from Red to Green, he should be able to either see or suss out with an ohm meter which pins are looping back to which.

He could also just terminate all 4 pairs of his "horizontal cable" on a 568-B jack right next to the Smart Jack, 568-B at the far end, test it end to end with his cable tester, use a regular patch cord from the Smart Jack to the first jack, and he will be golden at the far end.

Yes, burning 2 pairs that aren't needed, but covering whatever situation might arise in the pinout of the Smart Jack.

Tom, I know I'm probably beating a dead horse, but card mounting units are designed to provide either RJ48C/X or RJ48S, depending upon the card installed in the slot. I keep asking the question because the chances of a voice-grade circuit running to a wall plate in an office are pretty unlikely. These (ISDN/PRI) circuits likely terminate on a system of some sort, not in someone's office. A DDS circuit (T1) terminating on a wall plate in an office for data use sounds a lot more likely. I agree that either type of RJ48 can be accommodated by a standard 568B extension, but in his description of what's happening, the white/blue pair doesn't appear to be doing anything. Since only the blue and orange pairs have actually been connected, my conspiracy theory may hold some validity.

I keep bringing up the RJ48S scenario because I was called upon to extend one at a check cashing place using what we all assume was a 1,2,4,5 pattern and it turned out that my assumption was wrong. It was mighty embarrassing when I had to be corrected by a Verizon repair technician to use the white/brown pair and not the white/blue.

We haven't heard back from the OP, so we may never know what it turned out to be.

PS: I have a loop back plug that accommodates both RJ48C/X and RJ48S. I got it from a Bell Atlantic technician years ago. It was made by Nevada Western. It loops 1/2 to 4/5 and 7/8 since it's either/or, but never both.