Shared Connectivity

Voice is very sensitive to the quality of connection, and a lost voice packet results in a lost word in a conversation. Video, music and email, on the other hand, just request the packet to be resent before you even notice that it didn’t arrive the first time.

The key measure for good quality voice is jitter. This is a statistical average of the speed of a connection between two endpoints. There is less usefulness in taking a single test for jitter, though, because the quality of jitter can vary throughout the day.

Subscribers to Byphone can test their circuits with their call quality test. The test is a pre-recorded phone call from the connection point in your premises to the Byphone servers. This call is then repeated back to the original device that made the call. This call back is recorded, and the sound files of the original call and the recorded response are uploaded to the Byphone servers. The original call and the recorded call are then compared. A similarity score of 100 means that the sound files were identical. A score of over 75 is normally sufficient quality to support a good voice call.

You can download the recorded call back, too, so that you can hear a good representation of the voice quality.

The call can be made using the Google Chrome browser, by following the link on the Byphone website. This will give a one-off test result. This test uses Web RTC technology. This is an approximation of the type of call quality that you might expect. But, because Web RTC uses HTTP protocols, it is not an exact replication of a Voice over IP call. However, the result will give a good indication.

The web browser is not stable enough to make a series of tests. Browsers conserve power, and bandwidth, by going to sleep unless they are in use. To run a time series of tests, and to get an indication of how a circuit might behave over time, you use the test apparatus, Voxbox.

Voxbox is a small computer that is controlled by the web browser and makes a series of VoIP calls (SIP protocols) to the Byphone servers. The device is plugged into the connection point that you need to test. To only test the broadband connection, plug the device into the router or the switch connected to the router. To test the LAN as well, use an RJ45 socket. The device additionally needs a power supply.

Keep in mind that your firewall may be configured to block a Web RTC call! You can see if this is the case by using the connection test on the same website.

The Voxbox can be programmed to run the test at a variety of frequencies up to every ten minutes. The results of this time series of calls are also graphed on the website.

The device can also run a call and map the real-time jitter scores. This can be useful if you want to stress a network and see how it reacts.

The concern about sharing a data connection is that the voice data will be swamped during large scale downloads, such as synchronising data files or playing a video. The internet protocols are designed to use all available bandwidth. By running the test over a few days, however, you can identify whether or not your network uses programmes that are likely to interfere with the voice quality.