VOIP - friend or foe?

To say we were early adopters of VOIP (Voice over Internet Protocol) is an understatement.

A good friend and colleague Rob Darwin from suggested a VOIP based solution around 10 years ago. Once I worked out that VOIP was basically a fancy version of Skype with the ability to reduce costs and provide easier communication between our offices I was hooked.

5 common pitfalls and how to avoid them

Dedicated internet connection

By keeping office internet and voice calls separate you don’t need to worry that a large download will disrupt a voice call and you don’t need to tweak the system using tools to prioritise voice traffic.

It doesn’t need to cost a lot but we have dedicated ADSL connection in our main office that is only used for VOIP. We have tried premium services (£65 / month from a VOIP specialist) and budget suppliers. If anything quality and reliability was better with the budget supplier and we are happily paying Talk Talk £5 / month plus phone line costs.

Cloud or office based VOIP switchboard server

There are pros and cons of both approaches but if you have more than a handful of users I prefer a small office based VOIP switchboard server. We have two, one in both of our main offices serving 10 users each. It is also very cost effective as each server cost c. £210 (excl. vat). As the server is a single point of failure we actually have two servers in each office so we always have a spare loaded with a backup and ready to go.

Firewall issues

To get voice communication to our server (or phones) you do need forward ports correctly and this can be extremely frustrating. The best advice I can suggest is to use IAX2 as a protocol over the SIP protocol. It requires a single port to be opened and we find that connecting offices and remote users are far easier. Most VOIP switchboard servers will link via IAX2 but it can be challenging to find phones that use IAX2. By connecting our two offices via IAX and using on premises VOIP switchboard servers we can then use SIP phones behind our firewall.


Like any computer system VOIP systems can be the victim of hacking and other cyber threats. Possibly the most costly are if your server is compromised and hackers use your system to make free calls, often reselling these services to anyone who needs to make a long distance call to an expensive destination. Keeping systems patched and updated helps, as does use tactics such as limiting remote access to control panels and servers and carefully monitoring call records. We also limit the credit on our account and by using a pre-pay service you can ensure that worse case scenario a small sum is lost. Due to the cost of VOIP calls a small £10 top up lasts us over a month with 12 staff making a large number of calls

Choosing a supplier

We would suggest asking colleagues for recommendations and then asking potential suppliers to confirm if they include set up support, ongoing support and who’s responsibility it is to configure firewalls and manage the internal network.

We use Zycoo hardware for our VOIP switchboard server and Yealink phones both supplied by who also set up and support our systems.

For inbound phone numbers and outbound calls we use Magrathea Telecom,Gradwell and My Divert.

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