VOIP Tech Chat → Grandstream DP715 - problems w/echo

Hi, I have received comments from people calling when I am using the DP715 that they hear their own voice in the background. This does not happen when I take the call on my PAP2T/Panasonic DECT combination. Anyone else have this issue? Suggestions how to fix?

Turn down the volume on the DP715. It is very likely the microphone is picking up the audio coming out of the earpiece and echoing it back to your callers.

Thanks. I note that when using firmware 1.0.0.8 and turning down the volume, the echo is still in the background, irrespective of how loud the volume is. However, when using firmware 1.0.0.20 (beta) the echo becomes less and less as I step down the volume. I hope Grandstream has a fix for this in the final release of 1.0.0.20.

Could this be acoustic coupling between the handset speaker and microphone? As you know, anytime sound from the handset speaker is audible to the microphone, inescapable delays from transmission across the Internet (as well as encoding and jitter buffers) will cause the far end to perceive an echo.

I experienced this once many years ago with an older Grandstream phone. Troubleshooting revealed the culprit to be sound transmission within my telephone's handset. Inside the handset, I found a small, hollow passageway separating the handset speaker and microphone. As explained above, whenever sound passes through that cavity, the distant party hears an echo. I largely solved the echo problem by jamming a cotton ball into the void.

It might also be worth checking whether there is an Acoustic Echo Cancellation (AEC) setting in the DP715 that might be defeated.

I am not able to open up the case on the DP715, will likely damage the phone. As far as I understand echo cancellation should be enabled by default in the phine, no GUI where I can change/check this. However, I can change jitter settings. One setting is 'Jitter Buffer Type', a) fixed or b) adaptive and 'Jitter Buffer Length', a) low, b) medium or c) high. Do you have a recommendation on either of these jitter settings, or just try out?

From earlier posts I see that you are using the DP175 with Asterisk. It's a bit unusual for any well-conceived SIP hard phone to have echo. It's very possible that Asterisk is the source of your echo, most especially if you have any analog interfaces.

Have you tried to register the DP175 with an external SIP service and see if you have echo when Asterisk is not involved?

Just tried voip.ms Houston server, still the echo issue. The echo with Asterisk is actually less... [also tried to connect the DP715 directly to the DSL modem, still echo]

You are obviously not alone with this. Check out Grandstream's own support forums: »forums.grandstream.com/f ··· =15546.0

You may want to try opening a trouble ticket with Grandstream. Go to the support section of their website. It sometimes takes a couple of days for them to respond, but I've found that they always do, and they're usually quite helpful.

Edit: Ha - I just noticed that you already posted on the Grandstream forum. Hopefully they have a response for you.

Yes, posted a bit earlier today. Also opened a ticket, received quick response. Also, they made available a new beta version; 1.0.0.21. Just installed the latest version and the echo issue has improved. Hope to get rid of it altogether.

We recommend to use the BETA firmware version of 1.0.0.21 as of now, which has very less echo issue compared to the official firmware version. We are trying on improving this issue and would come up with the fix in the new firmware which will be released soon.

What makes this phone so attractive to you to begin with? Is it the price? Did you receive it for free or cheap on ebay? Why purchase a phone that doesn't seem to have a track record. I notice you open a thread a few days prior to this thread requesting information on this device, Apparently, you were seeking inputs after the fact. This phone might have hardware/design issues from the get go, any firmware tweak might solve the echo issue while creating others.

There are good IP phones out there with a good track record.

Simple, it is the only cordless IP phone I can get in the South American country I am currently in....... I wanted to give it a try, even though I have read that the DP715 has received mixed reviews. Note that updated firmware version actually do improve performance of the phone, just hope they get a final good version out soon.

Glad to see Grandstream monitoring this board and participating.