Pros & Cons of Business VoIP vs. Traditional PBX
Companies use a private branch exchange, or PBX, to connect their internal phones to their external lines and to carry out functions such as call forwarding and call holding. Business voice over Internet protocol (VoIP) systems can carry out many of the same functions at lower cost.
Cost
The main advantage of VoIP is cost, both for the initial investment and for monthly charges. A PBX system consists of a cabinet of electronic equipment in your office. Substantial costs are involved to purchase the equipment and for monthly charges. Lower cost is the principal reason for companies to adopt VoIP systems.
Reliability
A main disadvantage of a VoIP system is its reliance on the Internet to function. If you have a power failure or your Internet goes down, your company is left without any phone service. Traditional telephone lines get their power through the telephone wire and often function even during power failures. While VoIP services send your calls to the message center during outages and store them until service is restored, many companies keep at least one traditional phone line so they can make critical calls when the VoIP service is down.
Flexibility
With VoIP, you can add telephone numbers and telephones limited only by the bandwidth of your Internet connection. If your connection reaches capacity, call quality suffers. With PBX, you buy a system designed for a given number of lines and telephones. If you need a bigger system, you have to pay extra to add capacity.
Voice Quality
The voice quality of your VoIP calls depends on the quality of the Internet connection. If you are in an urban area with high bandwidth and have a high-capacity connection, your call quality will be similar to that for calls made over a PBX and traditional land lines. If your Internet connection doesn't have enough bandwidth or bottlenecks exist anywhere else on the Internet, your call quality deteriorates.
Emergencies
While VoIP service providers have tried to make 911 calling reliable from VoIP phones, they have had mixed success. With a PBX land line, the telephone company knows where the line ends and emergency services can find you via caller ID. A VoIP phone has no permanent location, as it will work from any connection to the Internet. You have to tell the VoIP service provider where you are using the service, but this has proved less reliable than normal 911 service, because the VoIP call may not connect to the correct emergency services number, and the location information may not transmit properly.