Can I reduce the latency in my VoIP phone line?

What to do if you have latency issues

By Neil Zawacki
Updated: February 03, 2011

VoIP has been known to suffer from occasional latency issues. Phone calls may be choppy, break up on you, or have echoes from time to time. There are several potential ways to reduce the frequency of these problems.

Sufficient Bandwidth

The first is to make sure that you have sufficient bandwidth available. It is generally suggested to have a minimum of 90 kbps, so you may need to switch to a better internet connection if you’re not allocated that much. It’s also a good idea for your employees to close any applications and videos that might be open and taking up bandwidth when they make a phone call.

Quality of Service

You can also purchase a router that is Quality of Service-enabled. This will allow you to shape the internet traffic on your system and prioritize internet applications as needed when the bandwidth is in use. You’ll want to set the UPD traffic to the ports that range from 10,000 to 20,000.

Old Phone Adapters

Old phone adapters can sometimes cause latency problems, so you should consider upgrading to a new one. They will generally cost you between $50 to $80, and tend to come with advanced features you may find useful.

Distance from Service Provider

Your VoIP phone line may suffer from occasional latency issues if the service provider is located too far away from you. Determine their physical location and consider switching to a closer service provider if one is available.


Firewalls are another possible issue, since they can slow down and stop VoIP signals that are attempting to pass through the system. You’ll want to update the settings to allow VoIP access if you haven’t done so already.

Analog Adapter to Hub

You may also be experiencing latency problems if the computer system running the analog terminal adapter is connected to a hub, since they only have 10 Mb shared medium. This can be remedied by connecting to a LAN switch port on your network router instead.


The U-law codec can occasionally help with VoIP latency issues. This is a specialized companding algorithm that reduces the overall quantization error in digital systems. You can download the U-law codec from numerous internet sites at no charge.


VoIP sound issues may also occur if you are using a standard headset connected to the computer. Consider purchasing a USB headset, USB phone, or noise canceling microphone as a potential method to improve the quality of your phone calls.

Reset Router

Sometimes, all you need to do is switch your router off and on. You’ll want to unplug the router for fifteen seconds before powering it back on and wait another couple of minutes for the connections to cycle back around, but this may be enough to get rid of the latency issues you are experiencing.

Overall, you want your latency to be somewhere under 150m. If you can get it that low through one or more of these methods, the choppiness and echoes should disappear and the experience much improved.

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