I am helping out a friend cable his new office.
We need to extend the 66 block to a patch panel using a 25 pair cable.
How should I terminate the 25 pair on the patch panel.
Which colors and pins am I using?

You're missing a bit of info, like what is it used for? You would need as little as one pair or two pairs if the system is a 2-pair system.

Now, it depends on what connections are made on the 66 block and the type of patch panel you have.

Check your phone system manual and you'd be better off calling in a pro to guide you if you're not clear. That, or have a lot of time on your hands.

The only hint is, if you're translating RJ-11 to 8-pin 568B panels, you'll use the blue and green pairs.

Carl

More information is really needed as to what is being connected at both ends? What is being extended and that is the 'original' wiring schematics?

Is the final use a:

• one pair
• two pair
• 4 pair

If it's a 2 pr: the a 568B would be WH-BL/WH-GR if you're trying to match USOC RJ-14

or

If it's a 2 pr: the a 568A would be WH-BL/WH-OR if you're trying to match USOC RJ-14

or

If it's a 1 pr: the a 568B would be WH-BL if you're trying to match USOC RJ-11

or

If it's a 1 pr: the a 568A would be WH-BL if you're trying to match USOC RJ-11

HOWEVER: When you install most (but not all) patch panels they will have color-coded paper inserts that will explain to the experienced layman what wire terminates where. BUT you have to decide is you need:

• 568A
• 568B
• 25 pr

If you can provide more information then we can provide correct information. Phone system? Which phone system - exact system is a must.

There's that echo....

1 White Blue
2 White Orange
3 White Green
4 White Brown
5 White Slate
6 Red Blue
7 Red Orange
8 Red Green
9 Red Brown
10 Red Slate
11 Black Blue
12 Black Orange
13 Black Green
14 Black Brown
15 Black Slate
16 Yellow Blue
17 Yellow Orange
18 Yellow Green
19 Yellow Brown
20 Yellow Slate
21 Violet Blue
22 Violet Orange
23 Violet Green
24 Violet Brown
25 Violet Slate

The first one goes on top. (White/Yellow/Red/Black/Violet)

Great, thanks guys.
I know how to terminate a 25 pair on a 66 block, Thanks for the input.
We are using CISCO IP phones with a CISCO Telephony system.

Diagramm:

T1 -> Smart Jack -25 Pair -> 66 Block -> 25 Pair -> Patch Panel.

I would like to know, what pairs from the 25 pair, go on which pins on the patch panel.

Thanks again, really appreciate your help.

Cisco IP phones use two pairs but are usually wired with four pairs each because they run on a LAN. I don't see an advantage to terminating on a 66 block first for the phones. Or are you planning to use existing wiring that you want to connect to a patch panel? Is this t-1 feeding data or dialtone or is it for ip phones?
All use different numbers of pairs.

I'm hoping he's only talking about extending a T1...you would not want to put IP phones on a 66 block!

Yes, I only want to extend that T1 to a patch panel using a 25 pair cable.
Thanks.

I would just use any 2 pairs that are not in use, one pair goes on pins 1 and 2, the other pair goes on pins 4 and 5 of an 8 pin modular jack.

If you're seriously only extending a T1 jack, why wouldn't you use an Allen Tel modular 8-pin jack with the proper shorting bars? That way, when you pull the plug it will loop back the T?

Carl

If you're extending a T1 you should use proper T1 cable with individually shielded pairs, or if you must use existing house cabling, split the Transmit and receive pairs onto separate 25 pair cables.