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BBATES Jun-07-00 02:22 PM
Does anyone know what a RJ-48c connector is? I have the pin-out for the connector, but I'm still not sure. What this is used for is to connect my isdn router to the isdn wall jack. I need a cable with an RJ-11 at one end and an RJ-48c at the other. Can anyone help me on making this cable? Can I use phone wire? Or do I use CAT5?

lbyard Jun-07-00 03:38 PM
In response to message 0
I quote the Black box Catalog:
"An RJ-48 plug is often mistaken for RJ-45. On the outside, the two look indentical--both are housed in miniture 8-position jack. The differenece is in the pairing of the wires.
In RJ-48, two of the wires are for transmit, two are for recieve, and two are for drain. the last tow wires are reserved for future use.
There are three subsets within RJ-48: RJ-48C, RJ-48X, and RJ-48S. RJ-48C and RJ-48X are very similar. Both use lines 1,2,4, and 5 and connect T1 lines. The RJ-48C is more common. The difference is that RJ-48X connectors have shorting bars. RJ-48S uses lines 1,2,7 and 8. It connects 56K DDS lines."

1 to 1
2 to 2
3 to 3
4 to 4
5 to 5
6 to 6
7 to 7
8 to 8

1 to 4
2 to 5
3 to nothing
4 to 1
5 to 2
6 to nothing
7 to 7
8 to 8

I can find no other info. I think you are going to need the pin-outs of each end of the cable. REcommend calling your service provider. Larry

BBATES Jun-07-00 10:06 PM
In response to message 1
I have the pinouts from the router manufacturer, but I am a little confused. rj-48c uses 6 wires, but the phone line I will be tapping into only uses 2 wires. My question is where do those 2 wires need to be?
I am having an isdn line installed and I bought an isdn router, but I didn't get the cable to connect the router to the phone line. I know the isdn line will only use the 2 wires my phone currently uses.

Thanks for your advise

BBATES Jun-07-00 11:23 PM
In response to message 1
I found an answer and thought I would share it

Subject: 21.0 ISDN Cabling

21.1 ISDN U-loop
ISDN Basic Rate Interface (BRI) is provided by a carrier from a central office (CO) switch to the customer premise with a two wire U-loop RJ-45 connector on the center pins 4-5.

RJ45 Plug
1 N/C
2 N/C
3 N/C
4 U-loop network connection
5 U-loop network connection
6 N/C
7 N/C
8 N/C

The EIA/TIA specifies an RJ-45 (ISO 8877) connector for Unshielded Twisted Pair (UTP) cable. The plug is the male component crimped on the end of the cable while the jack is the female component in a wall plate or patch panel, etc. Here is the pin numbering to answer the question, where is pin one?

Plug Jack
(Looking at (Cavity
end with the cable in the wall)
running away from you)

---------- / ----------
| 87654321 | | 12345678 |
|__ __|/ |/_ /_|
|____| |/___|

I found this info at:


lbyard Jun-08-00 01:58 PM
In response to message 3
Thank you. Larry

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