Grandstream GXP-4104 low gain
Submitted by richardyoder on Fri, 04/04/2008 - 6:13am.
I am using a GXP-4104 on trixbox version 2.6.0.5 with 4 incoming PSTN lines. We also have a mixture of GXP-2000 hard phones and a number of X-lite soft phones on PCs for extensions.
The problem is that the volume from an incoming call (PSTN) on the GXP-2000s (when the gain on the GXP-2000 is at max) is just a little bit too low to be heard clearly.
The system voice prompts and audio from SIP extensions is fine. This leads me to believe that the problem is in the GXP-4104.
I tried increasing the "Rx from PSTN Audio Gain" for all 4 channels from -12 to 12. While it does seem to get a little quieter on the low end, at about 3 and higher it doesn't get any louder but it does start to echo and can produce a little distortion.
It almost seems that the trixbox is doing some kind of automatic gain control at this point, but I'm just guessing...
Thanks in advance for any ideas on how to pursue this problem.
I'd like to know how to do
Tue, 04/15/2008 - 2:40am
I'd like to know how to do that as well, since we have some echo in our lines and i don't know if its due to the phones or due to the beronet card.
if i could playback the audio of the transmitted packets before they reach the phones then i'll be able to determine where the echo comes from.
To all: In general,
Tue, 04/29/2008 - 5:01pm
To all: In general, Trixbox runs in Linux, you can get a console/Terminal, then do following command before making a test call:
tcpdump -s 1500 -w capture.cap
If your trixbox have 2 NIC card, you may want to specify the interface by "-i eth0" or "-i eth1" option, depending on which card is communicating with the target.
Then you can try to render this trace file to a audio stream. You can use software called wireshark (www.wireshark.org) to render this.
If you hear echo from a phone, then the echo is generated from far end. if the other end hears echo, then it's your side generate the echo, if you have multiple legs, you can capture trace from each leg to determine which point is generating the echo.
Member Since:
2008-02-10