How to make the move from ISDN to SIP

ISDN is fast becoming a technology of the past. Today's telcos have networks that bypass traditional telephony signalling technologies for IP networks: the hardest thing they do is present a “legacy” connection such as an analogue line or an ISDN connection to a customer, as layering a non-IP service on an IP network is non- …

[Anonymous Coward]

Providers

While you say it's a move from a esoteric system to a commoditized system, I don't see providers making it easy for businesses.

As our supply contract is reaching the end of its term, we asked our current provider's local agent what our options and costs were with regard to 1) keeping the PABX and phones we had for another year or two on ISDN 2) getting a new system in

When they finally provided something it seems they were more interested in signing us up for a long term nearly all-singing and dancing cloud based SIP system with large investment in hardware on the desk than actually giving us a comparison of the available. (I presume they take their cut of the monthly charges so we represent a consistent income.)

Now we don't do anything spectacular with our current system (answer calls, makes calls, transfer calls) so personally, all I think we need is a black box on the wall that looks like a bunch of ISDN connections as far as our PABX is concerned.

[Anonymous Coward]

Re: Providers

At a guess you might want one of these: http://www.patton.com/voip-gateway/sn4170/ or similar

[ITSL]

Re: Providers

The problem is that many providers cannot make the shift from selling projects that generate large capital injections for their business and therefore load up hosted solutions with inflated handset costs and project costs.

It then makes presenting a true cost comparison very difficult. All my hosted proposals have zero capital expenditure, zero setup costs, no annual maintenance, no line rental and zero on-going call costs. The hosted model can then look very attractive.

[Anonymous Coward]

Are you sure?

"Unless your SIP service is coming from the telco that provided your ISDN service, the chances are that you can't port your existing phone numbers. If you're lucky then you may be able at least to get numbers within your own dialling code, but much of the time you won't Non-geographic numbers tend to be the way forward in such cases."

Very much not my experience. We have moved at least a dozen customers to VoIP and while there have been a few glitches in the number transfers, we haven't lost any. The various telcos have porting agreements in place - not necessarily with all other telcos though, so you might have to add that onto your shopping list when choosing a VoIP provider.

Also bear in mind that you might be under contract to your line rental provider who might (did, in one case) have punitive early termination charges... eg £500 per channel plus remaining rental for contract duration!!

[kain preacher]

Re: Are you sure?

Wow In the US it's different, You can port any number` you want to a cell of SIP provider.

[r00ty]

Re: Are you sure?

Pretty much the same experience as myself. A couple of years ago I shifted VoIP provider, picked up a set of local numbers to use for both personal/business calls, and at the same time thought I'd try to port my old London BT number at the same time.

No problem at all, completed on the day they said exactly.

VoIP is nowhere near as much of a mess of dodgy quality connections (if the call was lucky enough to go through) as seemed to be the case 8-10 years ago.

[ColonelClaw]

I Still Don't Need it

...and that's what we called it 15 years ago

[Anonymous Coward]

It never caught on as a domestic product, but the vast majority of businesses with more than a handful of lines who haven't moved to SIP use ISDN-30. It's cheaper and more space-efficient than the equivalent number of lines delivered over individual pairs of wires. I'm not sure you can even buy things like DDI over analogue lines any more.

[Down not across]

Dunno. BT HomeHighway was OK. Especially back when Freenet wasn't checking for channel bonding. Cisco 2503 was easy enough to configure to hang up before an hour was up and "redial" was quick. Effectively 128kbit/s leased line in late 90s for fraction of the cost.

My only minor gripe was that it didn't support Multiple Subscriber Numbering (for residential connections anyway).

[Anonymous Coward]

>I Still Don't Need it

It's all about latency.

SIP (VoIP in general) is sensitive to latency.

ISDN almost certainly provides much better latency than whatever it is you're using at home. Your SIP would work better over ISDN. As long as you're not running dozens of concurrent calls over it.

ISDN was never more popular simply because it was always a bit too expensive.

(not so great for streaming 4KTV mind)

[Mpeler]

I Still Don't Need it...

POTS calling the kettle black?

[Anonymous Coward]

The biggest pitfall I have seen is with people trying to run their fancy new VoIP kit over poor networks and SIP over terrible internet connections just to save a few £. Internally we still use a mixture of SIP for all our outgoing calls and ISDN for inbound and backup, when BT went down the other day I thanked god we did as I just changed the outgoing call direction to our ISDN, problem solved.

[Lee D]

The number of people who phone up to sell me VoIP and SIP and I end up hanging up because I can't actually hear what they are saying over their compressed / crackly / cutting-out line.

If you do VoIP, you have to do it properly. And that means QoS, priority and lots of spare capacity. You can't just lob it on your ADSL connection and expect it to work.

I suspect that most of them are home-workers with a company provided SIP line, but if you can't get your tech working on the sales call, what chance would I ever have as a customer once I'd bought in?

[usbac]

I agree completely. If you do SIP, you have to do it right. We run a retail call center. We moved from a PRI to SIP a year and a half ago. We have an actual fiber Internet connection running QoS with about 15% of our bandwidth reserved for VoIP. We have very few problems with call quality. As a matter of fact, I think when we do have poor call quality, it's on the other end.

The point about getting sales calls for VoIP that have very poor call quality is so true. Before the move to SIP, our at the time phone provider was trying to sell us their SIP service. We had a conference call scheduled with one of their sales guys, and one of their tech people. The problem was that that we couldn't hear either person because they were breaking up so badly! We told them to get lost right then and there.

That experience made us stay away from SIP for several years. If a major telco can't even make a sales conference call without call quality issues, what should we expect from SIP service?

We are with a provider that has good tech support, and has had fairly good service, at a great price. We are saving about $1500-$2000 per month in usage compared to the PRI we once had.

Add to that the savings of not making our $1100 per month lease payment on our phone system. We went with FreePBX/Asterisk, and bought our phones outright. We used an older Dell server we had as a spare (you don't need much server - you can run 10 phones on a Raspberry PI). In all we spent about $6000 for the new system (36 phones + 48-port POE switch). Full ROI in less than three months.

If done right, SIP can be great.

[Mookster]

Microsoft lync? (or Skype for business)

[Anonymous Coward]

Cheers!

[David 132]

Good article.

And an upvote for the term "electric string". I hadn't heard that one before. Perhaps I've just led a cloistered life.

[-tim]

Expense of gateways

One issue I've seen is that moving a small office from BRI (ISDN-2) to SIP is that the existing PBX power costs are going to go way up. We threw together a gateway out of an old cisco 3600 router and what used to be very expensive line cards. Its power use for the year would have exceeded the ISDN line cost. A new all VOIP phone system would also use a massive amount of power compared to some older phone systems. Our large office still hasn't used any of the cool VoIP features of its over priced phone system even though there are claims the old system just couldn't do it.

The power per phones is can grow quite a bit. At 2.5W max for the old 6 line analog phones with the big displays, they use 1/4 of the power of some of the fancy VoIP phones we looked at. Since these are on 24x7, their power costs should be considered since it may include new costs costs such as PoE switch, switch power, increased PBX power and increased phone power consumption, UPS and cooling for the switch/PBX.

I would like to get one of those patton gateways (mentioned above) but simple google foo doesn't even come up with vague lists and have the "call us to talk" mentality so they will fall off the potential supplier list fairly quickly.

Another issue is that SIP systems are often excluded by national telephone provider rules so the end customer is required to pay for all fraud even if the SIP provider doesn't even do simple protect against things like credentials from the wrong IP address or "Fake False Answer Supervision."

[Anonymous Coward]

Re: Expense of gateways

How did you manage to run phones for a small office over a BRI?

[-tim]

Re: Expense of gateways

How did you manage to run phones for a small office over a BRI?

It was BRI direct into the PBX. i.e. two phones could be used for each BRI channel.

[@Nick_Ward_ITL]

Free SIP & QoS

Just to add an alternative view to the suggestion that if it's free, it can't be much good. As a preamble, it's worth noting that a SIP Trunk with multiple channels is an abstract construct to make it a little easier for people to make the move from ISDN (or even multiple analogue lines for the laggards with ye olde PABXs) whilst giving the service provider something tangible to bill (bandwidth-based charging for voice might have seemed a little odd so wasn't attempted). Some of the Carriers provide wholesale SIP at no additional charge, provided that it's applied over data circuits that they provide, i.e. it's just a case of where they make a margin. The SIP Trunks themselves are provisioned from Carrier-grade kit (SONUS, Genband, etc) which is as good as it gets in terms of core network quality. As others have indicated above, the key issue with QoS is that if you mix voice and data without any QoS management and have a non-managed consumer-grade router on your data circuit (particularly ADSL) then disappointment is almost inevitable, e.g. if you try to upload a file while on the phone or try to have an important conversation after about 4pm when Internet traffic increases. As a final thought, bear in mind that the Class 5 switches used to deliver ISDN are getting on for 20-30 years old and supporting about 1.2M fewer ISDN channels than they were 10 years ago, so the move from ISDN to SIP isn't a maybe, it's a must.

[karykey]

ISDN for m2m projects?

What about ISDN users who involved into IoT or m2m projects, will providers still support it? What other technologies could be possible for such move, if you just need small amount of data or sms?

I was recently on a IoT fair and everyone was stressed about ISDN topic and proposed GSM connection instead of SIP.

[SamakshT]

Nice Post!!

I must say that traditional ISDN are no longer the choice for business communications. With increasing demand for flexible working and more responsive business communications, many small business firms are making a move from traditional phone lines to SIP. Not only it improves the customer service but also cut down phone bills effectively.