Digital phones and center pair question.

[jayjr1105]

Replacing an old Nor Tel system soon and the maintenance guy claims the phones are using the outer pair, not the center. Is this an issue with 1416 or 1408 phones or must the phones use center pair(red-green, blue-wh/blue)?

By outer pair I mean black/yellow or green/white-green pin 3&6

 

[smokinjoe2938]

center pins 4 and 5 tip and ring

 

[amriddle01]

There are leads available to make the crossover, or just crimp the ends on yourself, or change the faceplates etc etc

 

[jayjr1105]

But the verdict is, center pair only whether its RJ45 ends or RJ11 correct?

 

[smokinjoe2938]

yes normally on a rj45 it is the blue pair

 

[amriddle01]

Well it's output from the centre pins on the system (4 and 5) regardless of it being a Phone card, Digital card or TCM card. So how it comes out the other end depends on what you plug in and how it's pinned out etc

 

[jayjr1105]

But will the phone itself power up and grab a signal if the center pair from the system is pinned out to 3 and 6 of what you're plugging into the phone.

 

[amriddle01]

Yes, they aren't polarity sensitive either

 

[smokinjoe2938]

no it's looking for pins 4 and 5 on both ends

 

[amriddle01]

But what we often do is change all the BT sockets to 2 and 5 (as standard) and supply new line cords, then going forward it's much easier when they decide to swap them out for Avaya phones and you don't need to remember which sites are pinned out which way etc

 

[snowman50]

The way I do it with existing nortel phones is to connect the ipo pair to the existing BT Norstar /bcm socket which is on pair 3/4

Use the existing nortel Pstn lead and plug it into the Avaya phone.

So if it's hard wired then just connect your ipo to the existing pair.

If it's through a patch frame then use pins 2/5 as normal and plug your phone into the patch outlet using the rj45 cord.

 

[94astro]

Hopefully the jacks are wired with 2 pairs, usually they are when a system like Nortel or Panasonic that use the outside pair is installed. If not, I would definitely try to change the wiring at the jack. If you make linecords that swap the pairs at both ends, you'll end up paying for it when the customer decides to change cords.

 

[wireboy]

sounds like a 568a/568b problem

42

 

[TouchToneTommy]

Not at all. Some digital phone systems, notable Panasonic, use 6-pin jacks, but wire the phone to pins 2 and 5, the pair straddling the center pair (3 and 4). Lazy installers will terminate the I/W at the jack with the White/Blue pair on the Black/Yellow screw terminals, and fold back the other pairs. When you come around to install any other digital phone that requires a single pair, but on the more traditional Green/Red terminals of the jack, you have to go around to every jack and move the White/Blue pair over to the Green/Red screw terminals.

Now if the original installer wasn't so lazy, they would have terminated the White/Blue and White/Orange pairs on their normal terminals at the jack, punched all 4 pairs down on a 66 block, and run their jumpers from the Panasonic control unit to the White/Orange pair of the station cable, and all you need to do is run the jumper from the IPO to the White/Blue pair and change out the phone.