Max distance to extend PRI? 1

[daffymd]

We have a BT supplied ISDN-30 (Q931) that needs to be temporarily connected from the existing to the new Comms Room.

The distance is somewhere between 150 and 200 metres and the plan was to either connect via existing multicore or run a single Cat 5 cable.

Has anybody else extended a PRI over this distance?

Or are we asking for trouble?

 

[ISDNman]

According to my notes this is part of the ITU-T G.703 Specs as well as CSEP. According to my info it should be good for 300 meters of ABAM 110 Ohm twisted pair cable.

I looked at an older copy of G.703 and it is sort of vague in its wording, but gives a lower range of 345 meters. I glanced at a few ETSI documents and could find nothing further

So, based on this information I would say you should be fine. I would make sure there are no other E1/PRI signals in the same bundle and if you have the equipment I'd leave a tester up over night and verify you have no CRC errors.

Good luck

 

[daffymd]

Thanks for the information.

We are going to try it tomorrow evening so I will let you know if it works.

 

[daffymd]

We tried connecting a 300 metre drum of Cat 5 between the PRI and the Phone system and that worked fine.

So then we moved the Phone system to the other building and connected the PRI via the existing multicore (a distance of around 180 metres) and that has now been working with no problems for 24 hours.

 

[ISDNman]

Great!