Analog line very quiet

Hi All,
I have a customer with PBXact and 2 A200 analog cards when you are on call with a client the call is very quiet which sometime you think the call got dropped and asking the other party on call are you there this is my dahdi config thank you for your help.


I would love that :wink:
In any case, are you wishing to hear confort noise?

Assuming that when the client is actually speaking you have difficulty hearing them, something is very wrong. You already have the receive gain 12 dB higher than default. See

I assume that we are talking about FXO (analog lines), not FXS (analog phones). What kind of lines do you have (copper pair from central office, cable MTA, fiber ONT, etc.)?

You can call a milliwatt test number, e.g. in US 1 415 421 0020. Capture the traffic (to SIP extension) with tcpdump, copy file to PC and open in Wireshark, save the RTP stream and check the level. It should be about 3 dB below full scale. You can also check the level on the analog line with an AC voltmeter (1 milliwatt into 600 ohms is about 0.775 volts, but expect ~3 dB loss in the line). If you don’t have such equipment, you could listen on a corded analog phone (should be damn loud), or compare the level on the extension with calling the same number on a SIP trunk (if you have one).

If the level to the extension is ok, it’s likely that the IP phone or other device has insufficient gain.

Thank you guys,
Yes im talking about FXO, and yes when the other party talk yes i can hear good bot if im talking and other party listen because you dont hear any noise on the line you would thing you got disconnected i had it Rx 9 db and i raised to 12 today

I can’t think of any useful fix. While you could add some intentional noise, it would still be present even if the call was disconnected!

I assume that disconnect detection is working properly (if the caller hangs up or his mobile goes out of range, Asterisk sees the disconnect, drops the call and your IP phone stops counting time and showing the caller’s number).

If something goes wrong between the caller and his termination provider such that audio stops flowing without their provider (and you) seeing a disconnect, I don’t see any way to reliably detect it. Sorry.

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