Things to consider before choosing a VOIP supplier

More and more companies are considering changing to a cloud based or VOIP telephone system. This is shown by the fact that in 2014 sales of PBXs were down significantly whilst VOIP sales were up 10%. There are almost 100 suppliers in the UK. We have evaluated many of them over the last 6 years in order to decide which ones we would include on our brokerage panel.

To help you make your decision here are some key questions to ask and some advice on how to evaluate the answers.

What is the system built on?

In our experience the more successful suppliers have generally built their service on larger carrier grade platforms such as Broadsoft, Nortel CS2K (aka Genband), or Mitel. At the enterprise end there is also Cisco HCS. We have seen Asterix based-platforms struggle to scale and, as each system is developed differently, there can be difficulties if you wish to change suppliers

Is the Supplier part of the Telecoms Ombudsman scheme?

If they are, it shows they are sufficiently confident in their services to accept independent binding arbitration should customer disputes arise in companies of less than 10 employees. If not they may say they are part of ITSPA*. This does not offer the same protection, as it is more of a trade body. A list can be found at

Does any of the call traffic go over the public or private Internet?

If it goes over the public Internet it can affect call quality at peak usage times, so private is better.

Do you issue your own new numbers?

Does the company issue their own numbers or do they have to source them from another operator? This can impact porting in the future, particularly if numbers are bought in from multiple suppliers. It may mean that should you want more numbers in future these will be out of sequence. If the company is based in London, do they have access to new 0207 and 0208 numbers or do they just have 0203 numbers?

How many users do they have?

As a guide, the larger suppliers in the UK have at least 15,000 – 20,000 users. Whilst new entrants obviously will not have that amount it is a guide to levels of success.

Are they the supplier or are they reselling someone else’s solution?

Our experience is that it is always better to have a direct contract with the supplier as there are fewer steps in the support process should problems arise or should you need support.

What phones will be supplied?

It is interesting to note from our conversations with larger suppliers that they have largely standardised around Cisco, Polycom and Mitel. They have tried to work with other handsets but been unhappy with call quality or reliability. Also check that suppliers are using current phones; we have seen examples of companies supplying end of life phones, which could impact replacement if they break.

What are the call rates?

As a guide, UK landlines should be less than 1p per minute, UK mobiles should be less than 7p per minute. Anything higher and they are making excessive profits. There should be no minimum charges and no call set up fees. All calls should be billed per second.

What is the length of the contract?

Generally we don’t advise signing for more than 12 months unless there is a significant financial advantage in doing so. Some companies offer to rent or lease handsets if you take out a three-year deal. If you go for this option see if you can change suppliers before that date and reuse handsets with another supplier. On longer term deals check the flexibility and impact on costs of adding and removing users.

We would also recommend asking for a demo of their portal. This way you get to manage the solution. You can then judge how easy it is to use. Our free guide to VOIP can be downloaded from

Alternatively contact us for our free, independent advice. We have helped almost 200 organisations find the right solution for them.


*Internet Telephony Services Providers Association.