Intermittent Voice on your digital phone?

Although problems with VoIP and digital internet phones are not as common as the likes of Verizon would have you believe, they do exist. One such problem that I have the unfortunate pleasure of encountering is intermittent or choppy audio when using my VoIP Phone.Â

If you have read any of the blogs in our Techie corner you will have a good understanding of how VoIP works. With a VoIP phone call your voice is digitally sampled and divided into small sections. Each section is sequentially sent out over the internet embedded within an IP (Internet Protocol) Packet. The choppy or intermittent voice comes from one or more of these packets being lost, not sent or delayed in the network somewhere.

So what can you do if you have this problem with your own VoIP phone?

There are a few simple things that you can do before you phone your providers customer service line.

Try and characterize the intermittent voice. Is it in one direction only? Is it when you and your family are using the internet? Typically if you are on your VoIP phone it will be the person on the other end who can’t hear you properly and you will not experience the intermittent audio. A common cause of this is a lack of bandwidth in the uplink direction. Residential broadband internet such as DSL and cable are asymmetrical in nature. Comcast may promise 6Mbits, and they do deliver on their promise, however that is in the download direction i.e. to your PC or Internet phone. In the upload direction you won’t see more than 384Kbits. Try running a speed test when you are on the phone and experiencing problems and take a note of the bandwidth you are getting in the uplink and downlink directions. Compare it to when you are not on the phone.

Another simple test you can do is a ping test. Open a DOS command prompt on your PC and type the following command “ping -n 100” (don’t type the “”). Below is a screen shot of what you would expect to see.

What you are doing with this test is sending IP packets to The servers that host the yahoo website are sending a response back to your PC. The is the IP address of the server on the yahoo side. The bytes are how many bytes in the IP packet and the time is the round trip time for the message to be sent from your PC to Yahoo and then sent back again. Once the test has completed you get a summary of the results, the important one is the “lost” statistic, ideally this would be 0%. Any more than about 3% and the dropped packets will result in intermittent voice over your broadband phone. Try this test a few times and see if there is any correlation between using the phone, time of day or kids home from school and downloading music!!

It’s also important to check your setup and make sure you have followed the instructions your VoIP service provider sent with the ATA. This is particularly crucial if you have a router. Your ATA is effectively a VoIP router, it will give your voice packets priority over the data packets from your PC. This means that your voice packets will be sent out on time and will not be delayed even if you are downloading or uploading large files. The most common set up is is to have your modem, then your ATA and then your router.

Try the speed test and the ping tests with the ATA removed and again try and see any correlation.

If you see a slight drop in bandwidth or one or two more dropped packets while you are on the phone then this is actually a good sign. This means that your ATA is giving priority to your broadband phone at the expense of a few dropped packets of data. Data can be resent without a loss of content unfortunately voice can not.

These are all fairly simple test to run and you don’t necessarily have to take any actions based on the results however it will give the customer service technician you eventually call a lot of valuable information and it will save you running these tests while he’s on the phone as he’s “scripted” to ask you. Very often the technician can change your ATA settings to use a CODEC with higher voice compression thus using less bandwidth and resulting in less lost packets. They may also get you to call your broadband provider and have them check your connection. The above tests are also valuable as your broadband provider customer representative will no doubt ask you run them.

The one thing that I find somewhat ironic in the residential VoIP market is the fact that the likes of Verizon push their POTS telephony on reliability and suggest that VoIP is not so reliable. Probably half the problems associated with VoIP are problems with a users DSL or Broadband connection and not the actual VoIP application.

There are many triple play deals out there, VoIP, Broadband and TV all from the same provider like Comcast, these are decent deals, but you could find a cheaper service if you shop around for individual services. However having one company to contact when you have problems and eliminating the excuse “call the other guy it’s his problem” could be worth the extra cost.


[tags]Broadband Phone, VoIP, Choppy Audio, Intermittent Audio, Broadband bandwidth[/tags]

About the author  ⁄ Calum

Calum has been creating articles and blogs for WhichVoIP for many years. He has vast knowledge of the telecommunicators sector.

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