The answer depends on how you define the term "free". After much research into this subject I have managed to come to some interesting conclusions. I have looked at the following available options to assess their effectiveness for business conference calls.

1. Free conference calls using Skype
2. Free telephone conferencing using non-geographic numbers (NGN's)

Free conference calls using Skype

Many of you reading this will have heard of Skype which allows you to make free voice calls over the internet (Voice over Internet Protocol or VOIP for short). If have a PC or laptop and a good quality headset connected to a broadband internet service with sufficient bandwidth then you can hold a conference call with a limited number of participants without paying a thing.

The incremental cost of the conference call is zero, but the setup costs are considerable unless you already have the equipment described above. As the cost of computer equipment falls and bandwidths get better, more people than ever now have the required platform and hence Skype is an ideal solution for some people.

Our experiences with in call quality with Skype vary considerably. During quiet times when our internet connection is not busy we get excellent results in call quality, however it can be somewhat unreliable so we don't consider it robust enough for important business calls or ones where there are a large number of people.

Skype summary: The actual conference calls are free, but you need to have invested in the computer equipment and internet connection first. Limited number of participants and lack of reliability make it unsuitable for key business conference calls, where reliability is a must. There are other VOIP services that may be more reliable and economical then Skype, here are some other VOIP services compared

Free telephone conferencing using non-geographic numbers (NGN's)

This type of free telephone conferencing allows audio conferencing participants to dial into a non-geographic telephone number to hold their conference call. It's important that you understand what a non-geographic number is and how telephone operators - or "telcos" - charge for calls to them.

As the name suggests, a non-geographic telephone number (NGN) is a telephone number that does not terminate at any fixed location. Instead, when you call an NGN, the telco redirects the call to a "real" telephone number. In the USA the most famous type of NGN is the 1-800 free phone number. When you call a 1-800 number you have no idea where the operator who takes your call is located, they could be anywhere in the world.

Of course, telcos are not in the business of giving away free calls, so someone somewhere has to pay. In the case of the 1-800 number, the company you are calling pays the telco for the cost of the call.

Another type of NGN is a premium rate number. In the UK there are an array of different number ranges some of which cost callers as much as 1.50GBP (nearly 3.00USD!) per minute per call, such as this service. These are often used for "adult" services and chat lines. Companies wishing to promote a premium rate service hire a premium rate number from the telco and advertise their services with the intention of generating large numbers of calls to that number.

When customers call the premium NGN, the telco bills the customer for the call and gives a percentage of the call revenue back to the company who rents the NGN from them. In effect the telco and the company renting the NGN are sharing the revenue from the call. The important point to note here is that customers pay the telco not the company who is renting the premium NGN.

Teleconferencing companies who offer free telephone conference call services use this mode. The commission which the telco pays the audio conference service provider is used to pay for running the conference bridge, advertise the service and (sometimes) to make a profit.

Some telephone conferencing companies advertise this type of audio conference as being a totally free service. But there is almost certainly a charge for the call taking place. Therefore, to benefit from this type of conference call service you need to find an operator who can host a call at an affordable rate with a reliable connection.

This is the closest thing you can get to a truly free telephone conferencing, as they use the cheapest type of revenue generating NGN available in the UK. Namely, one that begins with the dialling code 0844. Some other companies use 0870 or 0871 numbers which are more expensive.

NGN summary: NGN based free teleconferencing services can be useful for small companies and individuals with moderate audio conferencing requirements, however these type of services are usually very basic and not suitable for larger organisations. For larger businesses, supporting greater numbers of participants, teleconferencing services tend to be a better option. As they are more likely to offer the support needed to make the call run uninterrupted on a clear line.