PRI 2CE1B and DB-15 cable to simulate ISDN connection

Unanswered Question
Nov 6th, 2007

I am looking to do a test at a lab (to simulate a real life design). I have got two routers, each router has got PRI 2CE1B interface card.

Can I connect these tow router by using :

E1 Interface Cable for 120-Ohm, Balanced Connections (with DB-15 Connector),to simulate ISBN PRI connection ?? or I have to buy an ISDN simulator for this purpose ?

Similarly If I want to simulate BRI between two routers (that have BRI Interface card) , can I use a specific cable for that ? or also I need to buy simulator ?


I have this problem too.
0 votes
  • 1
  • 2
  • 3
  • 4
  • 5
Overall Rating: 5 (1 ratings)
lgijssel Tue, 11/06/2007 - 22:23

To confirm what you were already assuming:

For ISDN BRI or PRI you will always need something in between.



zillah2004 Tue, 11/06/2007 - 22:29

Thanks Leo,

Are you saying that connecting for instance only a DB-15 cable between tow PRI interfcaes does not simultae an ISDN connection, unless there is a simulator devices (besdie the DB15 cable) locted between these two PRI interfaces ?

lgijssel Wed, 11/07/2007 - 00:52

That's correct. The BRI/PRI interfaces communicate with the ISDN switch for call setup etc.

This protocol requires a provider-side implementation which is not available on the router.


Paolo Bevilacqua Wed, 11/07/2007 - 08:44

No, that's not correct.

For ISDN PRI, you can connect router back-to back with just a crossed cable, and one side configured with "clock internal" under controller, and "isdn protocol-emulate network". See:

For ISDN BRI, depending if you are using hardware for voice or data, again use a crossed cable, add the command "isdn layer1-emulate network". See:

Hope this helps, please rate post if it does!

zillah2004 Wed, 11/07/2007 - 14:13

Thanks bevilacqua

Are you saying all I have to do is : to connect fastethernets for the two routers (my case I have got both of them 3640) by using cross over cable ?


Paolo Bevilacqua Wed, 11/07/2007 - 14:39

For PRI testing you need to connect the PRI interfaces, not the fastethernet.

Please follow the pinout for your specific hardware, crossing TX with RX. An ethernet crossed cable CANNOT be used for this purpose.

Hope this helps, please rate post if it does!

Paolo Bevilacqua Fri, 11/09/2007 - 01:34

Which thread have you found ?

Note, as I mentioned above, making back-to-back connections with BRI interface is only possibly with the BRI cards for voice, not possible with the ones that supports data.


This Discussion