Latency is the time it takes for data to travel from one point to another. In terms of VoIP, latency is the time it takes for your call to be connected to your recipient’s phone. When you’re on a traditional telephone line, latency is very low because the phone companies use dedicated circuits that connect directly between two locations. With VoIP, however, there are many more steps involved in getting your call from your computer to someone else’s computer. These steps can lead to higher-than-normal latency.
For example, if you’re using an Internet service provider (ISP) for broadband Internet access and a local company for local phone service, there may be several hops between you and the person you’re calling. If any of these hops have poor bandwidth or congestion, this can increase latency on your call significantly.