Business Telephone Lines – A Guide for Business Owners

Business Telephone lines - a guide for business owners

business telephone lines - a guide for business owners

PSTN, ISDN, SIP or VoIP? If you aren’t technologically minded, it can be difficult enough to work out which types of phone lines are available, let alone decide which one is right for your small business. We’ve made things simpler with a business telephone systems guide.

analogue lines - back to basics

Analogue telephone lines can still be found in business premises and residential properties throughout the UK. The analogue network is known as the PSTN (Public Switched Telephone Network). It enables you to make calls through your local telephone exchange, via a network of copper wires, but you need a telephone that’s plugged into the wall.

Analogue telephone lines provide users with limited functionality. You can only have one telephone number per line (although you can have extensions, enabling you to have more than one handset), and you’ll only have access to essential call features.

Analogue telephone use is declining in the UK, due to the increasing popularity of mobile phones and internet-based telephony systems. It’s likely to continue to fall as residential customers gain access to broadband services which don’t require them to have landline telephones, and those running businesses from home can modernise their telephone systems.

digital business telephone lines - all about ISDN

Digital telephone lines were first introduced in the late 1980s. They quickly became attractive options for businesses, as they provide far more functionality than analogue lines. Digital lines enable businesses to have multiple channels. They also allow companies to allocate Direct Dialing In (DDI) numbers to different departments and individual employees, so customers can get straight through to the person they need to speak to.

There are two main types of digital telephone lines in the UK: ISDN2 and ISDN30 lines. While both types of ISDN (Integrated Services Digital Network) lines have similar capabilities, the critical difference is the number of channels they can provide. ISDN2 telephone lines provide a minimum of two channels, with the option of adding further pairs of channels as required. ISDN30 lines, on the other hand, provide between eight and thirty channels per connection, but multiple connections can be used, allowing large companies to have more than 100 channels.

As discussed in our previous post, however, ISDN and PSTN telephone lines’ days are numbered. If you run a business, it could therefore be the ideal time to switch to internet-based business telephone lines.

Internet telephone lines - SIP vs VoIP

If you’re researching internet based telephony options for your business, you’ll find that two acronyms will keep cropping up: SIP and VOIP.

SIP (Session Initiation Protocol) isn’t actually a type of telephone system: it’s a protocol used to enable data packets to be transmitted between devices via the Internet. A SIP telephony system usually consists of internet telephone lines that are attached to a traditional onsite PBX (private branch exchange) telephone system.

VoIP (Voice Over Internet Protocol) systems often use SIP trunking to transmit data, but you don’t need to have a PBX system in order to use VoIP devices. Instead, you can make calls via a remote system operated by your service provider.

Internet based telephony solutions have many advantages for businesses. They can be more cost-effective, simpler to install, and more flexible than analogue or digital versions. Be sure you don’t miss out on our exclusive VoIP systems promotion which offers an excellent yet affordable way into the VoIP market.


If you have any questions about the types of business telephone lines available or any of the telephony solutions we offer, don’t hesitate to call us on 01252 241000 or fill out our enquiry form today!

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