Echoing, echo echo echo

Posts: 12 · Vonage Forum Associate Joined: Jun 21, 2006 Posts: 12

I have recently noticed an echo on my phones, and it is getting quite annoying. I have determined that it is only on my side, and those that I call do not hear it. It tends to get worse the louder I talk (although it might just be that it is more noticeable).

My setup includes:
10megabit Cogeco cable internet connection which is fed into a
Linksys WRT54GS router with QOS on, and set to give priority to the first port, which is where my
DLINK VTA is plugged in. It then goes to the main house line which has 3 phones connected.

I have done a speed test, and it has determined that I can have many phone lines with my connection. This happens on all the phones, and never happened with my Bell landline.

If anyone has experienced this, please post. As well, if you have solved it, or work for Vonage and can help, it would be greatly appreciated.

Thanks!

Posts: 105 · Vonage Forum Senior Joined: Nov 19, 2005 Posts: 105

Yes, I have a Dlink VTA and have noticed echo recently. Same as you, only I hear it and it get's worse the louder I talk. I think maybe the Dlink VTA transmits our voice a little too loud and we are getting acousting echo from the other end. That's my theory. Vonage said they made some adjustments to my account whatever that means but it did not seem to change anything.

Posts: 92 · Vonage Forum Senior Joined: Aug 01, 2006 Posts: 92

The echo is initiated from the other end. It is possible to reduce the Tx Gain (the transmit volume) on your device so you may want to ask someone at Vonage to do that for you. Alternatively you can ask the person on the other end to turn down their volume. You may also want to verify that the echo canceller is enabled on your device.. with Vonage of course.

- Kukk

Posts: 6 · New Forum Member Joined: Mar 22, 2006 Posts: 6

Echo is always generated on the other end... if the phone is too loud or put on speaker... Ask the other party to reduce the volume, usually it is the same person you use to call. It is the sound that can be heared in the microphone from the speaker or earpiece. Sometimes it is just a electric cross-over signal.

Posts: 105 · Vonage Forum Senior Joined: Nov 19, 2005 Posts: 105

Electrical crossover only happens when you go from Analog telephone lines to Digital lines and VoIP is digital end to end so you can't get it unless it happens in the phone itself which is not likely.

I believe the ATA has the capability to reduce acoustic echo so I am kind of concerned that the Dlink ATA has poor acoustic echo cancellation abilities.

Posts: 92 · Vonage Forum Senior Joined: Aug 01, 2006 Posts: 92

VoIP is digital end to end if you consider the PSTN gateway the endpoint. Nevertheless it is extremely unlikely that this would be caused by a wiring issue (electrical crossover) as the effect would be another persons call overlayed on your conversation.

There will be more echo on a VoIP line than on a PSTN since the echo cancellers are built into the device instead of the network. Usually echo occurs when there is also a delay on the line.

The echo canceller only has a short amout of time that it can find echo. If there is a delay on the line, it will be outside the range of the echo canceller and it will not work properly.

I would recomment testing the latency on your line as well as lowering the bandwidth saver to help lower the delay.

- Kukk

Posts: 105 · Vonage Forum Senior Joined: Nov 19, 2005 Posts: 105

dbarkeep wrote:

VoIP is digital end to end if you consider the PSTN gateway the endpoint. Nevertheless it is extremely unlikely that this would be caused by a wiring issue (electrical crossover) as the effect would be another persons call overlayed on your conversation.

There will be more echo on a VoIP line than on a PSTN since the echo cancellers are built into the device instead of the network. Usually echo occurs when there is also a delay on the line.

The echo canceller only has a short amout of time that it can find echo. If there is a delay on the line, it will be outside the range of the echo canceller and it will not work properly.

I would recomment testing the latency on your line as well as lowering the bandwidth saver to help lower the delay.

- Kukk

Your sort of right but it's not the same as analog and digital phone lines. The delay only becomes a problem, again, when your going analog to digital lines which your not with VoIP. The phone may be analog but the line is digital all the way. Echo and delay are not out of step so it's not an issue, again, with all digital! If the ATA does acoustic echo cancellation it will probably be designed to account for the inherent delays in VoIP. A regular phone line echo canceller, which your basically talking about is not designed for VoIP delays so it would have the problems you speak of.

Posts: 92 · Vonage Forum Senior Joined: Aug 01, 2006 Posts: 92

When you're calling a PSTN number it has to connect to the PSTN at some point. This occurs at the closest point to the endpoint where a point of presense (a gateway) has been built. So it is not really digital end to end.

The echo canceller on the adapter is limited by the amout of memory on the device. As a result the length of time it can account for, is limited by the router and the more importantly the cost. (of memory)

Most echo cancellers have less than one second to find and remove echo. If there is a delay in the line above that, they are unable to detect the echo since the original transmission has been overriden from the memory.

Unless I am mistaken.

- Kukk

Posts: 105 · Vonage Forum Senior Joined: Nov 19, 2005 Posts: 105

dbarkeep wrote:

When you're calling a PSTN number it has to connect to the PSTN at some point. This occurs at the closest point to the endpoint where a point of presense (a gateway) has been built. So it is not really digital end to end.

The echo canceller on the adapter is limited by the amout of memory on the device. As a result the length of time it can account for, is limited by the router and the more importantly the cost. (of memory)

Most echo cancellers have less than one second to find and remove echo. If there is a delay in the line above that, they are unable to detect the echo since the original transmission has been overriden from the memory.

Unless I am mistaken.

- Kukk

I can pretty much agree with all that. Your right about the PSTN connection on the other side. I guess I was talking about my own experience where I am getting echo on Vonage to Vonage calls which do not connect to the PSTN.

Your right about limitations due to buffer size. I wouldn't expect a sub $100 ATA to have a very large buffer or sophisticated echo cancellation

Posts: 92 · Vonage Forum Senior Joined: Aug 01, 2006 Posts: 92

Just as a clarification, most people do not experience much if any echo on the line, although it may be slightly more than a PSTN line.

This is due to the fact the echo cancelers built in to the PSTN are more sophisticated (140 years of testing), AND since all calls in the same exchange pass though the same echo canceler they require far fewer.

Since each Vonage (or any VoIP) adapter must have its own echo canceler, obviously they cannot be built with the same level of sophistication as the PSTN. It simply would not be cost feasible.

It's very rare that echo is caused by an electric crossover in the PSTN and most likely caused by high latency in your internet connection. While the adapters are not exceptional in echo cancellation they do a great job if the latency is low.

As time passes and the devices get better (memory cost decreases and algorithms get better) they will be able to remove echo mostly if not completely.

For the original poster it is possible that you internet connection has increased in latency. Especially if you are on cable, or perhaps, although unlikely, there could be an issue with your device.

Nevertheless I would contact Vonage to see if you can get a good tech support representative to help you resolve or lessen the issue. Often reducing the bandwidth saver will decrease the latency and remove the echo.

Edit: Spelling mistake

- Kukk