Why is the PSTN Long Tail So Long?

Jim Machi : Industry Insight
Jim Machi

Why is the PSTN Long Tail So Long?

telephone poles.jpg

Even though VoIP and IP communications in general is now dominating all landline communications, why is the PSTN still there?  Why doesn’t it just “go away”.   After all, there have been discussions about the PSTN sunset for at least the past 8 years that I know of.  This is mostly  driven by how hard it is to service the old equipment and that fact that new services we are used to using on our mobile phone wouldn’t possible with the current PSTN.  And in this blog post from a long time ago, you can see a discussion about mandatory PSTN sunset in 2018.  And yet, here we are in 2018, and I still see telephone poles, and I still see regular kitchen phones and sometimes when I go into offices I see real old PBXs.  So why is this?

Well, for one thing, it’s inertia.  You’ve had that kitchen phone in your house forever.  And it works.  And there is a bill you are paying.  So why change it?  There is even some benefit of that phone.  I lived in NJ during Hurricane Sandy.  With the power out, VoIP didn’t work and soon the mobile phones couldn’t be used because there was no power for them.  But I could still use the kitchen phone.  Inertia.  However, when I moved I confronted that inertia and I no longer have a kitchen phone.

Beyond that, just like anything, it’s a matter of economics.  There are literally billions and billions and billions of dollars of deployed working PSTN infrastructure.  And while new infrastructure typically will be IP based, there is this issue of deployed paid for infrastructure that is still working.  Maybe it’s getting frayed, and it’s hard to keep up, but it still works.  And if it works, why get rid of it?  It was paid for and it works.   But, there are some expensive maintenance contracts out there, so this is a good reason to upgrade / replace.  But some providers and enterprises are even forgoing maintenance contracts.   At some point they’ll need to upgrade and replace.  That is taking “it was paid for and it works” to the extreme.  But, there have been no high profile PSTN crashes that I know of, so it just keeping chugging on.

However, one reason this PSTN sunset is taking so long is an economic issue from a different sense.   The service providers just aren’t making the money on voice that they used to.  One impact of VoIP communications is that it drove down pricing as a whole.  So if the money isn’t there to get new equipment, or the equipment money is there only for data and for 4G/5G and emergency purposes for PSTN voice, then service providers will keep squeezing and squeezing. 

So there is no real good reason to change if they don’t have to.  And by this I mean if it works.

From an application solution standpoint, some solutions are still PSTN at heart.   Just put a gateway in front of a PSTN solution and you have connectivity to the internet and VoIP, prolonging that life of that solution.

All of this contributes to a very long PSTN tail.  If you need any PSTN connectivity equipment, Sangoma is still making PSTN products. While our customer base not only requires the latest cloud based IP infrastructure and services, there are also some customers that still require PSTN interface products for the reasons outlined here.   It is a very long tail indeed.


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