For anyone, including small businesses, to use Internet telephone service, they must, logically, be connected to the Internet. As a rule of thumb, old style dial-up Internet is not desirable. The speed at which the information flows back and forth is referred to as “bandwidth.” For many Internet subscribers, this bandwidth is measured as download, how much information can be RECEIVED by the device connected to the Internet, and upload, how much information can be TRANSMITTED from the device to the Internet. DSL (Digital Subscriber Line), cable Internet, and broadband wireless Internet all are offered in bandwidth packages. These are generally offered in megabits per second (represented as mbps) which are millions of bits per second. Bits are the basic unit of information transmitted across the Internet. All of these forms of connection can work for the use of VoIP services.
The real issue however is how much bandwidth is actually available to you. Since voice is a two-way application, we need to look at the lowest bandwidth number and make sure that this is sufficient. A typical connection from an Internet Service Provider (ISP) could be represented as 3 mbps download/1 mbps upload. Therefore, the 1 mbps is our limiting factor.
For most Internet telephone services, an average of 100 kilobits per second (kbps) or 0.1 mbps are required for each concurrent call using that Internet “pipe.” If there are three people in your office on the phones at the same time, you would need a minimum of 300 kbps (0.3 mbps). You would then be using up one-third of your available Internet bandwidth. Unfortunately, if someone were to suddenly start uploading a huge file such as a movie, this may draw away bandwidth and cause degraded voice quality. This is addressed by making sure that the devices connecting your location to the Internet have the ability to prioritize voice communications and allow other non-essential applications to use only what is left over.
Determining how much bandwidth you need is a critical component to ensuring that VoIP services work with great quality. Your ITSP should be able to work with you to make recommendations for maximizing your experience and satisfaction with your Internet telephone services.
Article by Phone.com.