atcomsystems.ca/forum Forums Wiring - Telecom Carriers - Trunks & Services Cabling Telephones Systems Wiring 25 pair termination

Well this is not by my choice. I'm an IT guy in a company too cheap to pay a true PBX vendor. So I've done a lot of cabling and I feel comfortable with terminating to 66 blocks as I have done a fair amount.

I was away for the weekend which is why the lack of response.

Again, for those that it appears not to have read or just misunderstood.

1 25pair goes from building A to building B. The 25 pair is terminated on both ends to a 66M50 block. The 66 blocks are mounted to drywall/wood not cement or brick. Each location is within a Telco/IT closet.

Stations are terminated to 66M50 blocks and then cross connect wire to the 25 pair.

Stations are dead at the jacks. So in troubleshooting I first unplugged the cross connect at the 66 block. I then terminated a small piece of cross connect to a jack. Terminated that to the opposite side of 25 pair. Still dead. Added bridge clips. Still dead.

I then took the blue/blue white pair of the 25 pair off the 66 block and terminated a jack directly to it. Voila, the station is up.

Yes, at one time this setup did work. A previous tech set it up and is no longer with the company. The building has been empty for about 2 years and now the owner is adding staff back to it.

I though possible corrosion to the blocks so I purchased brand new blocks and reterminated at both building A and building B.

This is a digital Axxess system.

I think I've answered questions asked. I'm really stumped here. Any input greatly appreciated.

And yes, cross connect wires are terminated to orange/orange white pair going to 66 block.

And to Jim, If you want to criticize go elsewhere and do it. I came here for help. Not because I want to but because I need it.

I don't want to be a telephone guy, I have no time for it, I'm an IT guy. Not my fault my company won't pay for the actual PBX vendor to come out and look at it. That's the economy we live in today unfortunately.

Sounds like this might be the direction you should be heading now that we know that you are working with a digital AXXESS.

So in saying reversed polarity, are you saying that when I'm terminating the cross connect I should swap the 2 wires and this is my problem?

Aha! I knew that was the problem. You should be using the blue/white pairs. Case closed.

Like Arthur I'm confused as to why if it works on the W/BL pair you would cross connect to the W/OR pair?

Easy, Arthur!!

Intertel uses the 2nd pair for their digital phones, thus the orange pair on a 568-A jack (and a USOC 2 or 3 pair jack). So he needs to cross connect from the White/Blue pair of the FEED cable to the White/Orange pair of the STATION cable.

If the OP happens to have 568-B jacks, he just needs to cross connect to the green pair of the station cable. Or, if he has USOC jacks, he needs to tie down the 2nd (orange) pair.

Thanks for clearing that up. I'll bet it's the A/B termination that's giving him grief. :thumb:

And they are polarity sensitive. I've had that problem a few times.

Since it works on the Cable and not the block, I would suspect the block.....However you already replace that....

So, her is what we know: In building "B" there is a feed cable coming in.
If you put a Jack on that cable directly, the phone works. (That shows that you are aware of the unique (Polarity and 2nd pair) termination that the phones require).
Once that cable is terminated onto a 66m50 block you are unable to get the phone to come up.

Can you please confirm this next part for us?

On a 66 Block there is 4 pins across (labled A,B,C, and D below)

A B C D
1 -> -> <- <-
2 -> -> <- <-
3 -> -> <- <-
4 -> -> <- <-

Assuming Feed cable is terminated down Column A and that the signl is present at column A. Put a butt set on pins A1, A2 and you should here a high pitch tone to confirm this.You should also have the same tone on pins B1 and B2.
Your cross connect should be coming off of pins B1 and B2. If you have sigle on A1 and A2 and nothing on B1 B2 I would suspect faulty pins on the blocks - The "V" of the pin not contacting the wire properly, but putting the Butt set on the pin allows the "V" to press into the wire giving a false positive. Depending on the condition of the tool used to punch the wires
down, can cause this. Sometimes rocking the tool horizontally while on th epin can close up th e"V" and allow better contact.
You did raise two things that makes me question the initial termination. These may or may not have any bearing on your problem though.
1) you pulled the Blue pair off of the 66 block...this isn't easily doe if it was terminated in the typical way - not sure if there is a correct tension guidline out there - since the wires are fairly tight. Terminating it back down would be even harder.
2) you reterminated the whole setup on a new block. There again, depending how the cable was initally installed, that may have proved somewhat difficult.