B100P + Asterisk + Snom m3 = echo?

Hi all,

I have setup a server with Asterisk 1.4.21.1 + mISDN 1.1.7. I have a B100P card. I have enabled echo cancellation in misdn.conf and I am using a quad Snom M3 pack (SIP-Dect). I have also tried various values for txgain/rxgain/echocancel/echotrainig to no avail. Currently my settings are txgain=0, rxgain=0,echocancel=256 and echotraining=2000.

I have very intense echo in most of my outgoing calls. I can hear my own voice and I have quite bad sound quality. Most of the times the other party doesn't hear anything strange. Sometimes though, I have had complaints of bad audio quality from the called parties too.

Does anyone have any suggestions? I'd really appreciate any pointers/hints.

hello,
please check few things:
1) how is your incoming calls? try an incoming call and play IVR？ what is the quality of voice?
2) replace your Snom m3 with xlite, what is the result?
3) cat /proc/interrupts? what is the result? please make sure other devices does not share IRQs with mISDN.
regards!
James.zhu

Hi and thank you for your answer,regarding IRQs, here's the output of cat /proc/interrupts:

[root@asterisk ~]# cat /proc/interrupts 
           CPU0       
  0:  220259586    IO-APIC-edge  timer
  1:          9    IO-APIC-edge  i8042
  8:          1    IO-APIC-edge  rtc
  9:          0   IO-APIC-level  acpi
 14:     205951    IO-APIC-edge  ide0
177:   23946344   IO-APIC-level  eth0
185:          0   IO-APIC-level  ohci_hcd
193:          0   IO-APIC-level  ehci_hcd
201:          0   IO-APIC-level  NVidia CK804
209:    1766777   IO-APIC-level  HFC PCI
217:  220149851   IO-APIC-level  opvxa1200
225:          0   IO-APIC-level  eth1
NMI:          0 
LOC:  220266679 
ERR:          0
MIS:          0

I don't see any conflicts, although I'm not very experienced in Linux. Do you see anything strange? The server has an AMD 64bit CPU, if that makes any difference.

I'll try the other two things you suggested ASAP and report back. Thanks again!

hello,
is it possible to change CPU to intel based and have a try.
regards!
James.zhu

Hi again,
I currently don't have another computer available for this. Do you think it might be the processor?

I really don't think so, as there's no problem whatsoever with calls to mobile phones for example (where to my understanding, echo cancellation is also implemented by the mobile company too). The problem only occurs in calls to landlines (especially PSTN phones)...

Could you try another h/w phone or soft phone?