[asterisk-users] Extremely choppy sound on some of our POTSnetwork calls; goes away with mute

[sdgesa gaeharth]

Below is the text of my original post. I am not sure what Codec we are  using.  The "Codec Preferences" phone setting shows, in order of  preference, G.711u, G.711A, G.729AB
  
  We are running asterisk-1.2.4 with zaptel-1.2.7 on Fedora  Core 4-2.6.14-1.1656_FC4smp.  It is  installed  on a Dell PE 2500 with 2x900 MHz processors and 1 Gb RAM and 1 SCSI  Disk. The server has a Digium TDM400P card which is connected to 4 POTS  lines.  The server is also connected to a 100MB  switched LAN where we have about 20 Polycom 501 phones with the latest  firmware updates. Nothing else runs on the server except an ftp daemon  which is never used except when a phone reboots.
  
  For about 20% of the calls to the outside world, the voice  on the other end of an outside line is incredibly choppy.   Enough to where we have to hang up and call  on a cell phone. It is always the same numbers that are choppy.  The funny thing is, if I press mute while  talking on a choppy   call, the choppiness goes away completely.
                I have tried: turning off ACPI, turning off APCI, moving the card to  another PCI slot, changing the RX/TX gains. There are no shared IRQs. I  have tested the lines by unplugging them from the asterisk server and  plugging them directly into an analogue phone. Using "cat  /proc/interrupts; sleep 10 ; cat /proc/interrupts" I see that there are  about 1,000 interrupts per seconds between the card and the CPU.
        I do not think it is a network congestion problem as intra-office  communications as well as voicemail retrieval are always perfect. The  Voip does not go over any routers, just a max of 2 switches with a 1GB  trunk. This happens even off-hours when the network isn’t being used at  all.
               There are never more than 2 people on the phone at the same  time and it is   definitely not an over-utilized processor.
  
      I have trying to figure this out for 2 months on and off with no success any help is appreciated.
  
  
  
    Thanks

Andrew Shelton <andrew.shelton at stemnetworks.co.uk> wrote:              v\:* {behavior:url(#default#VML);} o\:* {behavior:url(#default#VML);} w\:* {behavior:url(#default#VML);} .shape {behavior:url(#default#VML);}        st1\:*{behavior:url(#default#ieooui) }                    What codec are you using?
     
    How many phone? What load is the server  under?
     
     
     
            
---------------------------------
    
    From:  asterisk-users-bounces at lists.digium.com [mailto:asterisk-users-bounces at lists.digium.com]  On Behalf Of sdgesa gaeharth
  Sent: 05 October 2006 13:22
  To:  asterisk-users at lists.digium.com
  Subject: Re: [asterisk-users]  Extremely choppy sound on some of our POTSnetwork calls; goes away with mute
    
     
    1)Can anyone tell me how to do this on a Polycom 501?
  
  2)Can you explain why you think this any why it ony happens on some calls?
  
  Thanks
  
  Andres  <andres at telesip.net> wrote:
    
  >
  >
  > For about 20% of the calls to the outside world, the voice on the 
  > other end of an outside line is incredibly choppy. Enough to where 
  > we have to hang up and call on a cell phone. It is always the same 
  > numbers that are choppy. The funny thing is, if I press mute while 
  > talking on a choppy call, the choppiness goes away completely.
  >
  > 
  >
  Maybe you have silence suppression enabled on your phones. Try to 
  disable it and see if it helps.
  
  >------------------------------------------------------------------------
  >
  > 
  >
  
  
  -- 
  Andres
  Technical Support
  http://www.telesip.net
  
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