A quick look at Google reveals that in the light of The Great ISDN Switch Off, many folks are asking basic questions about ISDN itself.

There’s no sales pitch in this blog – I am simply a (hopefully) impartial independent telephone engineer working in North East England who writes blogs, and wants to provide something informative so that folks visit his site.

Why Are You So Passionate About This?

I occasionally encounter people utterly bamboozled by those in our business who see every change in the industry as a chance to misinform potential customers and force their products upon them for dubious reasons. I hate it, utterly hate it. Meanwhile, there is no need to panic. You’ve got (theoretically) until 2025 for you to deal with the Great ISDN Switch Off. Don’t let anyone scare you.

Are ISDN lines still used?

Remarkably, people are asking this. The answer is a define “yes”. It was reckoned that there were 2 million users in 2017. It may now have perhaps to around 1.5 million. However, it’s far from being old, obsolete and obscure technology. It’s still certainly mainstream. It’s far from “dead”. Typically, ISDN serves to deliver “phone lines” to a business phone system, but digitally, down copper cable.

What is an ISDN phone line?

“Integrated Services Digital Network” Put crudely, it’s like early-days “always-on” broadband, but for phone systems. Many simultaneous phone calls can share one line at the same time, just as many users can use one broadband connection at the same time. Also it can provide many individual direct-dial-in numbers for businesses. It’s stable, proven technology, also used extensively in the radio industry for reliable transmission between studios and outside broadcasts, as it’s so good. I wish broadband was the same…

ISDN”? “PSTN”? I’m Confused.

The telecomms industry loves using acronyms like this. Sorry. “PSTN” means “Public Switched Telephone Network”, that is the whole network, the lot, across the country and worldwide. If PSTN is the water distribution network of pipes in the ground and valves, ISDN is your own large-ish pipe to your premises. In the UK, BT (who own the network) have decided that they don’t want to maintain the network (PSTN) as it currently is after 2025. All calls will route via the internet (which is also carried over parts of the same network, but in a different way. Confused? Yes, me too.)

How Do I Know If I’ve Got ISDN?

If you have a “middle-aged” phone system of over ten users, it’s likely that an ISDN “line” will be your main connection between the system and the rest of the world. Check your bill! Somewhere there will be a mention of it. It may be described as “basic rate ISDN” “primary rate ISDN”, “DASS”, Q931, i421, or similar techie-speak. Billing is seldom clear, sadly. But it should be visible somewhere that you are being charged for it. Even dare to ring your provider and ask them what you are actually paying for.

Am I Going To Be Cut Off Very Soon?

No. You will even be able to lease new ISDN services until 2020. The proposed deadline for a final switch-off is 2025.

But A Salesman Told Me I Had To Switch as Soon As Possible.

Yes, of course. He wants to sell you something. He wants to convince you that you are facing “Phonemageddon” Right Now, and only he can help you (“just sign here”). However, there is A Very Big Problem on the horizon, but you don’t need to confront it just yet. What is it? Unfortunately, not everywhere has a stable alternative to ISDN yet. Let me guess your next question…

What is Replacing ISDN?

Put very simply, your calls will run over your broadband (internet) connection. There is much technical stuff I could bore you with here (that salesmen often do), but I won’t. You will probably need new phone hardware to achieve this, either in part, or a complete replacement, as your “lines” will be different, and you need a clever box to make them work at your end . Alternatively, this can all be done remotely, “hosted” in a server room somewhere in “The Cloud”. Effectively, your “phone system” is off-site.

We Have Fairly Good Internet, So We Should Be Fine, Then?”

Not really. “Fairly good” isn’t good enough. It needs to be “outstandingly good” to give decent voice service. Anyone trying to sell you a replacement must prove that it will actually work well, all of the time, even when local schoolkids start watching Netflix after getting home from school (yes, this can slow down your local broadband…). This is not like watching a Youtube clip, or looking a web page, where a delay or problem your speed or quality is irritating, but tolerable. Conversations need to be 100% reliable, 100% of the time, or voices can sound like The Dalek Who Swallowed Helium. Talking to a potential customer cannot be compared to Skype-ing a back-packing friend touring New Zealand  where you are prepared to tolerate occasional problems. Business communication needs to be perfect. Sadly, you may miss your ISDN lines when they are gone (if you don’t choose wisely, that is).

What Do I Need To Do?

Nothing in a hurry, yet” I’d suggest.

Is your broadband good enough for voice?

Do you have optical fibre running past your door, or are you three miles away from the exchange? If you do have fibre in your neighbourhood, it might be worth exploring the costs of getting a fibre service to your building. N.B. Having fibre to a local street cabinet (“FTTC”) is not the same as having it to your premises (“FTTP”). FTTC may well improve your broadband sufficiently to allow you to use it for your “phone lines”. FTTP definitely will. The quality of your broadband will determine if/when you cut over to the new service and do away with your ISDN lines. It’s time to start finding out.

Resist Anything “Too Good To be True”

Typically “A free phone system if you sign up for five years with us”. This is a common ploy, and sentences a customer to (potentially) a long period of contractual commitment to a (usually) unproven supplier who can raise prices when they want to. These deals seldom end well for the user.

Don’t commit or buy anything. Definitely don’t sign any contracts.

(I have I said this before? Don’t fall victim to a salesman’s drive to earn some commission.)

Hardware Issues – Your Phone system

Can your phone system be equipped with converters that will enable you to use it with the new . Check with supplier and maintainer. Don’t just let them force you to throw it out. Check the option to add “SIP trunks.”

What About Analogue Lines?

Yes, the same “switch-off” applies to them.  More in this blog

Can I Help?

Depending on mood and workload, I just might. Drop me a line here. Thanks for reading. The Great ISDN Switch Off will all turn out fine, I’m sure.