ISDN Pin Out

[capitol31]

Its been along time since I worked on isdn circuits. Can some one refresh my memory on what the pin out is? I'll be connecting it to a rj45 mod jack. Can I just terminate the jack using 568A or B. I can't believe that I don't remember. Thanks guys

 

[capitol31]

After a few searches I found that you only need one pair on pins 4,5. Is that correct? Why did I think you needed 2 pairs?

 

[ISDNman]

U interface is on the center pins (3 & 4) RJ11 or RJ45 is fine.

S interface requires 2 pairs.568 A or B is the right pairing. Pins 1 & 2 are not used. Pins 7 & 8 are used for power arrangment PS2, if required.

 

[capitol31]

Thanks, I'm not sure what type of interface they will be using. I guess if I wire it as 568B it should work no matter what type of interface, right?

 

[bkrike]

That all depends on the initial connection at the demarc.
(i.e. if they leave it tagged on a block you would still have to connect it to the IW somehow.)
If they leave it in an rj45 or smartjack, then you could use 568b at both ends of your run and use a patch cable to cross-connect it.

 

[capitol31]

The IT guy said its connected to the 66 block. What do you mean by IW?

 

[ISDNman]

IW = Inside wire.

If you are in the USA or Canada it will be the 2 wire U interface.

In most other parts of the world it will be the 4 wire S interface.

The S interface allows multiple terminals. If this is desired then there are certain desgin contraints etc.