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New Member

NM-2CE1T1-PRI Pinout Configuration

Dear Collegue,

I have NM-2CE1T1-PRI module card newly installed in our 3660 routers in some of the sites.

I tried to figure out, what type of interface I will use if the service provider will provide me a couple of E1's to connect to the other sites.

I am quite a little bit confuse regarding the connectors between the RJ48 and RJ45. Is this two connectors are the same pins or size? What are the pinouts if you want to use the channelized E1's for data and what are the interface I will use? Do I have to connect the E1 link from the frame directly to NM-2CE1T1-PRI module with RJ45 or RJ48 or there is a special interface provided by cisco.

Please I need your expertise ASAP if you can and I really appreciate it.


  • WAN Routing and Switching

Re: NM-2CE1T1-PRI Pinout Configuration


Officially :yes the RJ-48 is different from RJ-45.They both have 8-pins, the difference is that RJ-48 is slightly bigger.You will know the difference only when you take both the connectors in hands, otherwise both looks same.

In my country, the PRI line is simply a pair of 2 wires.One pair for TX and one for RX.

1,2 are Rx and 4,5 are TX.Rest 3,6,7,8 are not used.

You just need to crimp it.Dont know in ur case.

Unofficial TIP: You can connect the RJ-45 male to RJ-48 female and it too works.

Check out the following links.

Need more information then revert back.

Pls rate the post if it had helped.



New Member

Re: NM-2CE1T1-PRI Pinout Configuration

Hi JD,

Thanks for the reply. I tried to insert the RJ45 connector to one of the E1's port and it seems the RJ45 is bigger than the port but I did not try it again. I try to purchase the RJ48 in one of the shops and he told me that RJ48 and RJ45 are the same that's why I asked for help for the confirmation.

One thing more if the Service Provider will give me an E1, should I connect the wire directly to the E1 with RJ45 or RJ48 to the router or Do I need a special connectors.

Please need your advice and for confirmation.


Re: NM-2CE1T1-PRI Pinout Configuration


I dont know in ur case, but I am always able to insert RJ-45.Never mind that.

If u are purchasing then its fine.I would recommend an IO Box installed in the wall and connect that to the card using RJ-48 cable.Make sure you have correct TX and RX pairs.View the attachment.

When the link and config is ok, then the Green CD led will come up and orange ALM led will go.

Hope this helps.

Pls rate the post if it had helped.




Re: NM-2CE1T1-PRI Pinout Configuration

Make sure you ask your provider to deliever 120 ohm balanced. E1's many times are delivered on 75 ohm coax cable. You will need a balun to convert this if the provider does not do it.

I have not found a document that says size of the connector is different between rj48 and rj45. Many manufactures say rj45 on their e1 interfaces so it causes lots of confusion.

I have always used normal LAN patch cable to go from the router to the provider equipment. You may need sheilded cable if you are going long distance but I have yet to do that.