Call quality issues with VoIP generally come down to the Internet speed. Bandwidth describes the maximum data transfer rate of a network or Internet connection. It measures how much data can be sent over a specific connection in a given amount of time.

Why does the Internet quality depend on your Internet service?

VoIP phone systems run completely over the Internet. Because of that, your call quality is 100% dependent on the Internet service that you use. Low bandwidth can lead to poor quality calls due to slowly delivered data packets, or even a system that can’t send or receive calls. Keep in mind that the number of computers at the same location and on the same network as your phones, as well as multiple concurrent phone calls, can impact the availability of bandwidth.

How much of your current bandwidth is needed for high-quality voice calls?

The bandwidth that our VOIP phone service requires depends on the number of concurrent calls you want to make.
Number of Concurrent Calls    Minimum Required Bandwidth  Recommended speed

1                                       100 Kbps Up and Down                       3 MBps Up and Down

3                                       300 Kbps Up and Down                       3 MBps Up and Down

5                                       500 Kbps Up and Down                       5 MBps Up and Down

10                                      1 MBps Up and Down                          5-10 MBps Up and Down

Things to Remember

  • Your Internet connection will generally have more download speed than upload speed.
  • Computers and other devices connected to the Internet will lower your available bandwidth. Streaming and downloading both use large amounts of bandwidth.
  • If you are using close to the full capacity of your connection, traffic will bottle neck. This can result in latency, which will directly affect call quality. A good rule is to plan to use 85% of your Internet connection’s advertised ability.

Test Your Connection

Run this Speed Test to determine the bandwidth of your connection.

NOTE: Latest versions of Adobe Flash Player and Java may be required to run the speed test in some browsers.

The speed test will report latency, download speed, and upload speed. Divide the lower of the two numbers by 85, which is the amount (in kilobits per second or kbps) that each call will consume in both upload and download bandwidth.

The result

The result will tell you the number of concurrent calls your connection can support. To allow for quality and in the presence of extra features such as Busy Lamp Field, it is safer to assume that each phone you are using will need nearly 100 kbps of upstream and downstream bandwidth delivered consistently to and from your Internet service provider.

NOTE: The upload and download speeds that your Internet service provider delivers vary over the course of time depending on many factors, such as the type of connection that you have and network congestion in your market area.

Analyze the Speed Test Results

Ping (Latency)

  • Ping – The amount of time it takes for your computer to communicate with a server. On a VoIP phone call, this constitutes the latency (or delay) between you and the person you’re speaking with. Small delays aren’t noticeable, and a ping speed below 100ms is generally acceptable.

Upload and Download Bandwidth

  • Upload and Download Bandwidth – Typically Measured in Mbps (Megabits per second) the upload and download speed let you know how much data you can work with.

    Download bandwidth

    It represents how much data your connection can facilitate from your Internet service provider to your location. When you are hearing conversations your phone is downloading small pieces of information and playing the audio back to you in real time. Upload bandwidth is in the opposite direction. Technically you are uploading your voice and conversation to your Internet service provider who then delivers the information to the proper destination.

    The upload bandwidth

    It represents how much data you are able to send out from your location at a given time.

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