Skip to page content
Client Hub Tel 01892 830111

PSTN: Whats that?

By Russell Gower-Leech, Technical Solutions Architect | Published 20 Apr 2020

PSTN or Public Switched Telephony Network is the traditional (landline) system providing telephone connectivity since the 1800’s using a mixture of underground and over ground copper wires. 

That’s great but why should I care?

The reason we bring up PSTN is that it is being retired in 2025 and replaced with a contemporary Voice over Internet Protocol (VoIP) service. VoIP effectively carries telephone calls over an internet connection. Most providers have been slowly upgrading their infrastructure and porting customers over to VoIP within the core network transparently. 

Great so no need to worry? 

Domestically you won’t really need to worry as your providers are already working on this change/have made this transition but for businesses there are some considerations: 

  • What’s my current telephony solution? 
  • Am I in a contract and for how long? 
  • What am I seeking to achieve for my business?
What's your telephone solution in Kent

What’s my current telephony solution? 

Understanding what you have now and what it does (or doesn’t) do for your business is the first step in deciding what you need to do (if anything).  

The vast majority of businesses have a physical phone system, i.e. a dusty metal box in the server room which connects their desk phones together, handles call routing, voice mail, etc. In many cases these solutions can support VoIP and if you’ve been keeping up-to-date with maintenance or renewed your contract it probably already is and there’s less to worry about. 

Some business will have a hosted telephony solution in which case you are pretty much in an optimal place as there’s no deprecating hardware to worry about and your staff can be highly mobile (pat on the back for you). 

Some however will still have PSTN based systems and it is these that will need to be replaced before 2025. Now granted that’s 5 years away but this brings me nicely onto my next point.

Am I in a contract and for how long? 

Most telephony service contracts are 3-5 years and auto-renew for a similar term so getting out or changing the service mid-contract can be difficult or expensive. So the first thing to do is find out when your contract is up for renewal so you can investigate other options with adequate time to budget and make the switch without disruption.  

What am I seeking to achieve for my business? 

I touched on this earlier but it’s the real crux of any investment you need to make. Businesses like call centres or hotels need a large volume of devices and need to keep both device costs and recurring costs down. So on-premise telephony systems utilising VoIP tend to be a good balance, but does have challenges around multiple sites and remote access, none insurmountable but they tend to be more complex and costly. 

Other businesses, where there are multiple small offices and staff are highly mobile or need to cater to staff flexibility, prefer a fully hosted solution as a better fit as staff can use PC’s or smartphone apps to tap into the system from wherever they are. These systems typically also include instant messaging, call presence features so you can see who is online or on a call and integrate with screen and files sharing which is great for remote presentations.  

This approach has the added benefit of reducing maintenance disruption and single points of failure; hosted solutions utilise clusters of server and networking equipment to act as one, so if one component fails or is taken down for maintenance, the phone system itself is unaffected. Single physical systems obviously do not have this same luxury, so ensuring you have a service contract to cover hardware issues and also a plan to divert numbers to mobiles is essential. 

The final thing to consider on the appliance front is age, as I mentioned telephony contracts tend to be long and auto-renewing so there can be a skills gap as the equipment ages and the telephony provider loses staff or moves on to other systems, over the last 12 years I have seen first-hand these issues where units are miss-configured, can’t be updated or reconfigured as the skills simply aren’t in the business any more. Again, with hosted solutions this typically isn’t an issue as the equipment has to be maintained and cycled regularly. 

In summary now is the time to ask these questions, plan ahead to ensure the switch over doesn’t affect you, that you are not locked into a system which is restricting your business and you can utilise this opportunity to make your business more agile.  


Learn more about Microsoft Business Voice the new VoIP solution from Microsoft integrated into Teams.


Contact Us