There is no question about the cost savings advantage that Voice over Internet Protocol systems have over legacy PBX systems, but business owners still have to consider the potential additional costs related to mobile broadband data if they choose to forward calls to company smartphones.

Improving Communication Quality

VoIP quality of service is determined by various factors. Aside from bandwidth priority to handle heavy call volume, there is also the matter of voice quality, which depends on the speed of the internet connection as well as by the audio codecs used. A small business office with just a few phone lines may be able to achieve QoS starting at 4 Mbps; a call center will need more than 10 Mbps. With regard to the highest voice quality, which is known as HD audio, the solution is determined by codecs and by the hardware utilized. The highest voice quality can be achieved with the G.729 codec, which happens to consume the most data; this is not a problem at the office because just about all commercial internet plans offer unlimited data, but it may become an issue when VoIP calls are transferred to smartphones.

The G.729 HD audio codec transmits at a rate of 32 Kbps; this translates into 240 kilobytes of data consumed in a minute, but this calculation must be doubled since VoIP calls use both inbound and outbound data. A minute-long VoIP call taken on a smartphone running on cellular data will consume 480 KB, which is about half a megabyte. When you take into account video conference calls handled by VoIP systems, the H.264 codec consumes about 3.75 MB per minute.

Generally, commercial and residential internet services delivered by fiber optic cable do not feature data caps; in this case, employees who take their company smartphones home can connect to their residential networks without having to worry about using up their cellular data plans. Employees who are on the road must be mindful of their data caps as well as potential roaming costs.