These 2 factors are vital for the good audio quality of your phone call, and the amount of simultaneous calls you want to make.
Bandwidth Calculation For One Phone Call
Audio Codec: G-729a Incoming Bandwidth: 23.63 Kbps Outgoing Bandwidth: 23.63 Kbps Total bandwidth needed for 1 phone call: 47.26 Kbps
In most cases (ADSL), your ISP will provide more download capacity than upload, you therefore need to look at your upload capacity in order to determine how many simultaneous VoIP calls you can make.
For example, if you have an upload capacity of 120 KBs, you can only make 5 phone calls at the same time, even if you have more download capacity.
As for the bandwidth usage, 1 GB will give you a talk time of 2700 minutes, if your ISP gives you a capacity of 512 KB per month, you will have a talk time of 1350 minutes per month.
Bandwidth Calculation For Multiple Simultaneous Calls
