[dougdrury]

I have an SPA400 connected to 4 PSTN lines. My SPA400 is at firmware 1.0.0.9. SPA 9000 hardware version 1.0.5/software version 3.3.6. Using four SPA942 phones on a gigabyte network.

Whenever we pickup the phone to answer a call, we hear serious echo on our side. Very distracting. The caller does not hear the echo...only the person using the SPA942. It sounds the same on the 4 phones...echo and noise. The static is also only on our side, but it is pretty obtrusive. From a callers point of view, there are no issues. The echo happens when using the handset or the speakerphone.

Should I upgrade to the latest 1.0.0.c version of the SPA400 firmware? I didn't see anything about call quality in the release notes. My gut tells me to look at the SPA400, but is there anything on th SPA9000 that might do this as well? I have left all the SIP settings at their defaults.

Some of my SPA400 settings are:
G.729 Coder
DTMF Power: -130
Answer after 1 rings
transmit gain: 0db
recieve gain: 0db
impedance: 600 ohms


Thank you for any help.

Doug

[eric]

Echo is usually the result of an impedence missmatch or high gain settings.

Which phone company are you connected to?

[dougdrury]

Thanks eric!
Verizon Wireline in Lompoc, California.
I have 0db gain on the spa400. After doing a little more troubleshooting, it seems that the echo only happens when picking up an outside call. When making an outbound call, there is no echo when the called party picks up.

I think that one (or three) of my PSTN lines are fliped tip and ring.

My SPA400 status shows:

Line 1: 49 V On-Hook
Line 2: 50 V On-Hook
Line 3: - 48 V On-Hook
Line 4: 50 V On-Hook

Shouldn't they all be around 48V On-Hook?

[donws]

Doug,

Did you ever resolve your noise/static issue on PSTN calls? My incoming and outgoing PSTN calls are also noisy but VoIP calls between my SPA942s stations seem fine.

My SPA400 is running firmware version 1.0.0.12, and here are a few of the key settings:
G.711U Codec, 20ms packets, VAD off
Answer after 2 rings
transmit gain: 0db
recieve gain: 0db
impedance: 600 ohms
Line Status: 43V (positive)

I'm not sure which settings on the SPA9000 are relevant here (since only PSTN quality is poor) but under regional->miscellaneous tab, I have "More Echo Suppression" set to "no".

I'm located in NC and BellSouth is my PSTN provider.

The noise/static is most noticeable when the remote party stops speaking and/or when I'm talking with someone who speaks softly. Voice quality on the remote end is also poorer (and perhaps softer) than it ever was before installing the Linksys SPA setup.

Thanks,
Don

[dougdrury]

donws,
My client got so fed up. We went to an Avaya one-x setup. Clear as a bell now.

Sorry I couldn't help any.

Doug

[donws]

Doug,

Thanks. Unfortunately, I may be forced to dump this Linksys system as well if I can't find a fix. With the current background noise and voice quality, it is really not suitable for business, if even casual conversation.

Has anyone managed to achieve clear, noise free PSTN calls via the SPA400?

Humba, I read you had more luck with a Grandstream device, but I assumed you were talking about flexibility/features versus voice quality/noise?

Regards,
Don