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Community Member

ISDN to ISDN, w/o NT1 for Training/Testing

Good Day! Can anyone tell me if it is possible, or if you have connected two router's S/T ports with a crossover cable (without using the high voltage connections)? This would be for testing/labs.

For example, connecting 2-2504s using a Cat-5 crossover cable. The cable would just be using pins 3,4,5&6 for transfer of data.

I would appreciate any information anyone could supply.

Thank you for your time.

5 REPLIES
Community Member

Re: ISDN to ISDN, w/o NT1 for Training/Testing

No, it's not possible. Unlike a T1 back-to-back config where you can simply use HDLC keepalives to provide your layer 2 connectivity, ISDN requires signalling from the switch to establish that the circuit is indeed up. There's a lot more to it than just voltage and circuits being complete, as DEBUG ISDN Q921 and DEBUG ISDN Q931 will show.

Community Member

Re: ISDN to ISDN, w/o NT1 for Training/Testing

Thank you for your time and info. Barry

Community Member

Re: ISDN to ISDN, w/o NT1 for Training/Testing

Rollin:

Hello! Thank you for responding to my question. You mentioned a T1 back-to-back configuration. I am still researching this, but if you don't mind helping once more, can I use a crossover cable between 2 NT1 units? Conversely, could you point me in a direction for more info?

Thank you again for your time.

Best Regards,

Barry Mason, CCNA

Community Member

Re: ISDN to ISDN, w/o NT1 for Training/Testing

No this is not possible on the 2500 series. We do have some products that support network side bri but I am not sure if you can make calls from one to another if they are directly connected.

Josh

Community Member

Re: ISDN to ISDN, w/o NT1 for Training/Testing

Thank you for your time and info. Barry.

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