3CX - PSTN, ISDN or VoIP? – Part 2 - Geek Guru

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3CX – PSTN, ISDN or VoIP? – Part 2


Continuing in our series exploring the different types of lines available to use with 3CX systems, we focus on PSTN standard lines.


PSTN stands for Public Switched Telephone Network. While it’s really a catch-all term for the wide spectrum of telephony and communications systems used by the general public, in the terms of our article and topic of discussion, it’s often used to refer to the standard analogue telephone services provided by many networks. The technically correct term is POTS or Plain Old Telephone Service (yes, that’s actually the official name), but many prefer to refer to it as PSTN.

However you refer to it, PSTN or POTS is the standard analogue telephone system that’s been around for many, many years – and is still extremely useful. Fax machines, franking machines and modems up to 56k were (and still are) designed to transmit digital signals across an analogue network. Many of these kinds of systems support communication over different types of network now, but most will still function across a PSTN analogue line.

For residential lines, businesses who only need a single line, sole traders, or as an additional or emergency line, PSTN lines still have a firm footing in the telephone line market.

For most small businesses, PSTN is not really something we’d recommend to be used on its own. However, it can come in useful when your business is running primarily on VoIP or ISDN and you want a backup line in case of any malfunctions or breakdowns.

Standard PSTN lines are easy and relatively cheap to install, and usually don’t require any extra cabling. They also don’t require any power source as they’re powered by the local exchange, so they are great for use in emergencies. You can have multiple PSTN lines installed if you wish. If you want an additional line to use solely for a fax machine or franking machine, PSTN lines can also be useful there, as the line rental for them is also usually quite cheap.

PSTN lines are supported by 3CX through the use of a gateway, so you can use your 3CX PBX system and PSTN lines together with VoIP to get some extra functionality and a backup line if you wish. If the VoIP line is not available for whatever reason, you can make and receive calls through your standard PSTN line.

In our next blog, we’ll take a look at ISDN and its basic functionality, some of its advanced features and how to get the most out of it with a 3CX PBX.


If you’d like to discuss 3CX Systems, VoIP, ISDN or anything else IT or tech-related with us, give us a call and we’ll be happy to help you in any way we can!

Call us on 0845 234 0580 or email us at info@geek-guru.co.uk

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Posted on by Emily
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