PSTN Sunset-Consequences and Opportunities

By Peter Aggus

The PSTN, the public switched telephone network that operates in parallel to private IP networks and the internet, is winding down and users will find many locations where PSTN based service is no longer offered. The telephony world is moving to VoIP and you need to understand the consequences of that move as well as the opportunities it may offer—like reduced costs.

?Background

The Plain Old Telephone Service (POTS) provides the ability to set up a ‘circuit’ through a complex network of cables and switches collectively known as the Public Switched Telephone Network (PSTN). Whilst we still need POTS as a service, the duplication of maintaining the PSTN alongside new IP broadband data networks, required for modern internet service, can no longer be justified by the income generated. POTS, as a legacy PSTN service, must switch to the IP network.

Timescale

Some countries have completed PSTN shutdown. Others have set end dates. The US and Canada have not set a timescale yet—largely because of needing ways to support extreme rural communities where there is no current broadband data service.

Rural areas will continue to be served by legacy PSTN services for some time as broadband IP data service expands.

Consequences

Where adequate broadband IP service is available, local phone companies no longer have to provide legacy PSTN service. Whilst existing services currently face no mandated change, new services will have to be provided via IP technology, either individual VoIP lines or SIP trunks (the IP equivalent of PSTN PRI service).

Opportunities

Many companies look at technology as an investment with a payback period. If they spent thousands on a new phone system a decade ago and expected a 20 year life from it, they are reluctant to scrap it early.

Our experience is that IP transport technology is significantly cheaper than PSTN technology. A legacy PRI digital service could be costing over $700 a month and providing less than 2MBit/s bandwidth. In the data world, you can get Gbit/s bandwidth for lower cost. You could switch to a VoIP SIP trunk over your internet access.

If your PBX still has life left in it, you can get a device that sits on an IP network, looking like a SIP trunk interface, but providing a PRI port to connect to your PBX.

You need to look at costs carefully because a total VoIP solution might be cheaper—even if it does mean premature retirement of the PBX.

Basic phone lines, including Centrex services, which many firms still use, cost several times as much as a VoIP equivalent service.

Fax lines, POS terminals and alarm systems can all switch to IP networks and enjoy reduced costs, even though some have special technology needs.

What You Need To Do

PSTN technology is in its sunset years. At some future time you will need to change. Right now, your PSTN technology is likely costing significantly more than equivalent VoIP technology would—so changing sooner might make sound economic sense.

You need a business plan to identify ways of meeting your business needs. You should consider all options, including complete replacement even if systems are not life expired. What matters is the overall cost and switching to VoIP can end up costing significantly less.

If you’d like to discuss options, or to comment on this article, please email me at? [email protected].

?This article is reproduced from the November 2023 edition of ?The TMC Advisor

?2023 TMC Consulting

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