This forum includes tips for maintaining the best audio quality possible with the Ooma System. If your Ooma system is having issues with dropped calls, static audio or echo, look here for assistance.
#108128 by cacophony
Mon Mar 25, 2013 11:41 am
Pretty frequently time I've noticed a quality issue with the very first second of a call.

For example, if I call Comcast on my Ooma, I'll hear:

"you for calling Comcast"


"[unintelligible word] you for calling Comcast"

Whereas on my landline I'll hear:

"Thank you for calling Comcast"

The rest of the call is fine, it's just the first second that has the issue. Any ideas?

My hookup is cable modem -> Ooma -> router, and I have 22Mbit down/ 6 MBit up speed, with about 15 millisec latency according to an internet speed test.
#108130 by cacophony
Mon Mar 25, 2013 12:00 pm
If it helps, I ran the recommended speed test (not sure it matters, but I did it on a VM Ware virtual machine instance due to not wanting Java installed) :

download speed: 21582 kbps
upload speed: 6283
download consistency of service: 94%
upload consistency of service: 96%
download/upload test type: socket
Max TCP delay: 230 ms
average download pause: 2 ms
min round trip time to server: 29 ms
average round trip time to server: 38 ms
route concurrency: 1.0
download TCP forced idle: 0 %

jitter you -> server: 6.4 ms
jitter server -> you: 6.0 ms
packet loss: you->server: 0.0 %
packet loss: server->you: 0.0 %
packet discards: 1.2%
packets out of order: 0.0 %
estimated MOS score: 4.1
#108131 by lbmofo
Mon Mar 25, 2013 12:45 pm
You shouldn't see packet discards or loss. The loss of audio at the start of the conversation maybe due to something else but might as well check out your modem readings...

murphy wrote:Connect to the status web page in your cable modem
Find the downstream and upstream power in dBmV and the Signal to Noise Ratio (SNR)…
The downstream signal power should be between -10 and +10 dBmV. (Some say between -15 and +15 but I feel that is pushing your luck)
The SNR should be 35 or more.
The upstream power level should be less than 55 dBmV.

With DOCSIS 3, you'd want the numbers to be tighter...downstream between -5 and +5.... upstream less than 50. If your modem numbers look questionable, do a “restore factory default” on the modem status page & reboot or do a hard reset if the modem has a reset button.
#108134 by lbmofo
Mon Mar 25, 2013 1:41 pm
Although your numbers are acceptable, they are not very ideal.

Should try to reset (from the modem status page, "restore factory default" and then "reboot") and see if your packet discards go away.
#108138 by cacophony
Mon Mar 25, 2013 1:56 pm
Here are the modem values after the restore/reset:

Signal To Noise Ratio 35.3 dB
Power Level -10.6 dBmV

Upstream Value
Power 50.9 dBmV

I did rerun the speed test and got 0% discards this time, as well as twice the upload speed (11 Mbps!). But some of the other numbers look a bit worse (like consistency of service at 84%).

Why did the power level decrease downstream?
#108139 by lbmofo
Mon Mar 25, 2013 2:00 pm
The downstream power became is your download speed now?

The upstream power improved..... keep monitoring the modem values to see if that -10 downstream improves toward zero. But for now, as long as the VoIP speed tests turn out okay, you should be good. If that -10 doesn't improve as you sample reading periodically, you should call your cable company, have them come out and fix it.
#108141 by lbmofo
Mon Mar 25, 2013 2:24 pm
cacophony wrote:How would they fix the power level? I own the modem BTW.

-10 means your incoming signal is kind of there are a number of things they can do from the street and beyond to reducing number of splits, quality of splitters, quality of connectors on the house side.

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