Hello,
Does anyone have a cure for echo on a docsis phone system? I use Arris TM402Ps, a CMTS 1500, Asterisk and a VoIP provider that is the same as my T1 provider so the network is fine. The upstream SNR is 34.9db. I have this old lady that says she hears her own voice. Believe me, I'm not ruling out mental illness either. Could it be the phone?
Thanks,
emkowale
one of the main issues of echo is a high latency (inband voice delay, this should be less as 150ms) and a bad isolation on the hardware of the other side.
If the other side of your customer is using a phone with an option for a hands-free speaking option, that the spoken words of your customer returns over the microphone of the other side back to him. If the inband voice delay is low, your brain will not recognize the echo. If the inband voice delay is go higher and the isolation on the other side is low, the spoken words will come back with an delay which your brain is to sense as nasty.
The main problem of VoIP is the high inband voice delay in the network (to compare with the POTS) which is originates during the A/D operation on the DSP, through the network back to D/A.
On the HFC-Plant there no issues for echo. On the HFC-Plant will come packetlost. Jitter is also no problem on DOCSIS, if you using UGS-ServiceFlows in Upstream.
regards,
wittmann
sorry for my poor english
Hey,
Sry if I am not much help - Wittmann already mentioned most of the issues valid for VoIP. I would definitely ping check latencies in all directions, try to make a call from behind the modem in the NOC, than try with softphone from the same VLAN as the users of CMTS are, than directly, same VLAN as your uplink, try calling back that old lady and if possible someone in the neighborhood. Also, check your Asterisk - as I understand - you are provisioning with packet cable, your customers are connecting to your asterisk server and than are being routed onto some other gateway of your telephony provider - so, how are the calls from the network to your asterisk, how are calls from your asterisk towards the VoIP gateyway....etc ..that would probably help you pin-point where the problem occurs.
and talk to us more than :)
.play.open.minded.
You're both helpful. The plant is clean. RF is awesome there. SNR is great. We use the Arris TM502Gs to connect to the Asterisk server using SIP. I thing there may just be some weird signals in the area. I'm trying to see in people with cordless phone vs people with corded phones have issues. I've noticed a lot less problems since I've gone from the crappy cat3 phone wiring in the building to to coax network I put in. Now I have 7 Mediatrix 4124's for sale if anyone needs them. :)
I still need to figure out things like random touch tones heard on the line without anyone pushing any buttons, dropped calls, static and of course echo. Any links you have would be great. I have 4 other systems I manage and I have never had these problems.
Thanks again,
emkowale
heyya, just another two cents.
we also found out that, if things are not set OK, sometimes we have different results when using softphone from the eth port of the modem, compared to using regular phone plugged into eMTA port of the same modem. So, using softphone from different nodes/parts of your network might also help identify whatever problems you might have - and to what OSI layer your problem belongs.
.play.open.minded.
If anyone has anymore questions on this subject, they can contact me. I've been forced to become the resident expert on the subject. Here's a nugget. If the electricians do a crappy job, "yer gonna git echo". Move the cordless phone away from any power strips and off of the top of the TV.
;)
emkowale