It depends on the type of PRI. What I call real, telco based PRI, the original PRI that was available before anyone ever heard of SIP trunking is in my opinion much more stable and reliable than SIP or SIP based PRI that cable companies supply.
If it's real PRI I would always choose it over SIP any day.

True PRI, when working the audio quality and reliability is rarely an issue. But true PRI is getting very rare as it is more expensive for the providers to provide in local exchanges and to customer premises. Increasingly, any PRI to customer premises will actually be SIP somewhere upstream.

SIP is almost 25 -years old now and yet it still hasn't settled down to be a mature and stable technology. People keep adding new bits, competing bits, conflicting bits, onto a huge pile of standards that each SIP provider then implements and interprets differently. PRI had the advantage of being a set of standards that telcos agreed between themselves before any new standard was published. SIP on the other hand is open to every man and his dog and if an idea gets enough supporters it gets an RFC.

Rant over. SIP is here to stay, whereas PRI is going away. Get used to SIP.

Stuck in a never ending cycle of file copying.

Just compare the number of settings in Manager!

I agree with Nortel4Ever
Real PRI if you have the choice and don't mind the extra cost (mostly).
It is also a 4 hour response time should it go down vs SIP and your Internet goes down.
HOWEVER
with SIP you can have a secondary Internet connection that keeps your lines working

PRI over SIP has basically an electronic device that converts it on site back to PRI - WHY - the system can do SIP so why the extra point of failure.

Joe
FHandw, ACSS, ACIS

I'm not sure about the situation elsewhere but ISDN was 'stop sell' in September this year and will be switched off by December 2025.

ipohead - that's the UK

In North America things last a lot longer. We still have customers asking for a Nortel phone system when they call us

They use up all the old equipment until it has to be thrown out because there are no other options. There are also regions that have no fast enough Internet to make PRI over SIP work.

Joe
FHandw, ACSS, ACIS

Talk about old things not dyeing in the US like they should. I changed jobs a couple of years ago and now work for a company that has an NEC system from around Y2K that is using ground start lines. We occasionally get telco techs out that I have had to explain how to troubleshot them.

Dermis and feline can be divorced by manifold methods.*
*(Disclaimer for all advise given)--'Version Dependent'

@budbyrd Ha!!! We still support Norstar systems with analog DIDs.

Hit does an analog DUD work?

analog DID is basically an analog line that sends the DID number via DTMF to the phone system.
I had to learn that when I came to Canada in 1999 as I had also never seen that in my 15 years prior. No such thing in Germany
Same with ident-a-call for analog phone lines or even call waiting on analog lines

Joe
FHandw, ACSS, ACIS

The only analog DID I ever worked with was pulse dial. Was an old Merlin Legend.

Dermis and feline can be divorced by manifold methods.*
*(Disclaimer for all advise given)--'Version Dependent'

I think Germany who had the biggest market for ISDN ceased it a few years ago.

SIP seems to have worked well over the years here but of course it is adding several points of failure. Of course it is about half the price.

We still use AC15 and analogue MFCR2 on our air traffic voice system.

ISDN30/Megastream has a massive advantage over SIP in the call setup time and latency but support from BT/Openreach is getting worse (and slower) by the year as spares and engineers become fewer.

ADTRAN has a sip to PRI conversion device has anyone tried using this? I believe from what I read it allows a PRI to be used but without being forced to pay for all 23 channels for a full PRI that most demand. This way the smaller user could still keep their pri and get the ID but only have a small number of channels to fit their business traffic size.

I have worked at locations that used the Adtran SIP to PRI converters. They were provided and managed by the telco. They work and are a reasonable replacement for a true PRI.

Dermis and feline can be divorced by manifold methods.*
*(Disclaimer for all advise given)--'Version Dependent'

We have Adtran SIP to PRI converters as well. The one problem that we've run into is a limitation on connection duration. I know it's not normal call duration, but the calls "only" last from 4 hours to a max of 12 hours- then the call will automatically disconnect. Of course, with the old- strictly PRI trunks, a call could be up for days! It sounds like a timer situation in the SIP realm. It's easy enough to just reconnect, but telco doesn't seem interested in tracking this down. Might be more effort than what its worth. Any thoughts or experience with this issue?