SPA3102 PSTN Echo Problem

Discussion in '3CX Phone System - General' started by mkieffer, Jan 3, 2010.

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  1. mkieffer

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    Hi everyone,

    I've tried just about everything I could find about fixing the echo problems with the SPA3102 adapter but nothing seems to be working. The highest gain I have been able to set on the PSTN To SPA Gain has been 3 anything higher than that I get the horrible echo.

    With the setting at 3 calls are still quite and it would be very helpful to have it louder. I am located in Canada and Bell provides the phone service. I am not sure if I have the FXO Port Impedance set correctly or not but there must be something else I am missing. I have searched Google a bunch of times but I am unable to locate any information stating what it should be set at in Canada.

    I have attached a couple of screenshots of the current configuration of the device. Let me know if you need any other configuration information, any help would be greatly appreciated.

    Thanks,

    Mike

    Both Images are from the PSTN LINE Tab

    [​IMG]

    [​IMG]
     
  2. israr

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    Mike:
    i had similar problem with Digium's Switchvox where i was using AT&T lines and Analog lines card from Digium.

    I temporarily relocated the phone system to my office for testing purposes. Echo disappeared. I took back the system to client's office and echo appeared back.

    I have worked with AT&T several times and they are unable to remove echo. They show on their Demarc that there is no echo and give up.

    I suggest tying the system at a different location/different lines/connection.

    israr malik
    http://www.greatsys.com
    http://www.chicagopcrepairs.com
     
  3. leejor

    leejor Well-Known Member

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    The settings have been optimized for North America (you just have to look at the timezone and caller ID settings to see that), so... if you are going to "tweak", start from the factory default settings. Change one setting at a time, if it doesn't do anything, change it back.

    I find the voice quality, myself, pretty good when everything to do with echo or gain is just left where it is. Many times your level problems and echo can be caused by the condition of the phone line itself, how far from the central office, any other devices on the phone line, any long runs in the home with nothing plugged in at the other end. If you are using ADSL and have a filter located at each phone, try using one filter where the phone line first comes into the home and you split the phone line to go to the modem and ALL the other phones/devices.
     
  4. mkieffer

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    Leejor,

    I am currently 10 city blocks at the most from the central office, there are some other analog phones plugged into the line along with the SPA3102. There are a few runs in the house that have nothing connected to them, I am going to disconnect them and see if that makes a difference. I am using ADSL and there are filters on all of the phones.

    The wiring that comes into the home is older and there isn't a demarcation point on the side of the house (although I really wish there was :cry:) so having one ADSL filter will be out of the question.

    Tomorrow I am going to disconnect all of the other devices from the line (other than the ADSL modem) and see what happens.

    Mike
     
  5. leejor

    leejor Well-Known Member

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    The other thing, I forgot to mention...if you are using a Hub at all, in your network, get rid of it and use a Switch instead. A hub has been known to slow things down enough to cause echo, besides...they're just...old.

    I would also change both Gain settings back to the default of "0". Boosting the levels more than absolutely necessary is almost guaranteed to cause problems.

    Are the calls at a low level when using an ordinary phone on the line, NOT using 3CX? Is it all calls or just some? Incoming and outgoing? It may be that you will need to get a phone, to use with the ATA, that has an amplified handset. If the phone line level itself is low then report it as a problem to Bell, it could be a a bad linecard at the central office.
     
  6. mkieffer

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    Sorry I meant to reply a couple of days go but I had some other things that took priority over figuring out this problem. I have cleaned up some of the wiring in the house and adjusted the gain getting in the PSTN Line config (see screenshot) the echo is just about gone at my end whatever is left I can put up with.

    However there is now a new problem. When the other party is talking there voice tends to fade in and out to the point where I cannot hear them at all. Anyone have any ideas on what would be causing this issue? Also the calls are still quite, but the audio fading in and out is a bigger problem at this moment.

    Also to leejor,
    There are no Hubs in the network. None of the other ordinary phones are quite it's just the phone's (there are two a Linksys SPA942 and a SPA942) that are on the 3CX PBX, if I make a call out the PSTN or one comes in I have to turn up the volume on the phone almost all the way. But if I go and make a call to the other extension on the PBX the volume is overwhelming, so I can't see the PBX causing any issues.

    NOTE: 3CX is installed on a Dual Intel Xeon 2.6Ghz With 2GB of RAM

    Also there isn't a phone plugged into the phone port on the SPA3102.

    [​IMG]
     
  7. leejor

    leejor Well-Known Member

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    The "other" phones are using ...what. I has assumed that they made use of the FXS ports on the 3102. If the level problems are occurring only on the SPA942's then I would concentrate on options on those. Of course it could be a set hardware problem, did you buy them out of a back of a truck in an alley? Obviously, it's not caused by the gateway if other sets are not having the same issue.

    The FXO Port Impedance (for North America) should be left at the default of 600 ohms. I'm not sure of what the "Global" option changes that to.
     
  8. mkieffer

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    The other phones are plugged in as normal, until this is up and working 100% the are a mix of analog phones and the two VoIP ones for testing.

    Like I said in my last post "If I make a call out the PSTN or one comes in I have to turn up the volume on the phone almost all the way. If I make a call to the other extension on the PBX the volume is so loud its overwhelming" When I make a call between extensions the audio is fine, it's lots loud and there isn't any problems with the audio fading in and out. Therefore I would find it hard to believe that there would be something wrong with the phone's themselves

    I did not buy the phones from the back of a back of a truck in an alley, one came used from eBay the other was purchased from a computer supplier here in Canada.

    I change the FXO Port Impedance back to 600 and made a test call, it has made a very small improvement but still not where it should be. Also I unplugged all the other phones that are on the line made a test call and it didn't make any difference.
     
  9. leejor

    leejor Well-Known Member

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    My comment was a bit of a joke...but, I have talked to people that "got a really good deal", only to find out that the phones were so cheap because they had been returned because of intermittent problems, that the seller didn't disclose.

    I take it then that the only VoIP phones you have used are the Linksys sets then? Have you tried using a 3CX softphone to test the levels? Or, you can set up the FXS port on the 3102 as an extension and plug in one of your analogue phones. Have you tried changing the "PBX delivers audio" setting in the extension on 3CX?

    If the same "low Level" problem occurs with other devices, going through the 3102, then it sort of points to the 3102 as being the problem. It could be faulty, that is a possibility. First of all i would do a factory reset (**** R E S E T) and make sure you have the latest, stable, firmware load. Before upgrading firmware ALWAYS do a search using the firmware load name and the word "problems" or "issues". The latest isn't always the best, some have been know to cause more problems that they are worth.

    From a "factory fresh" 3102, only change the fields necessary to get the gateway to register and calls to go through.
     
  10. ve2dat

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    look on cisco web site "how to reducing the echo"

    http://www.cisco.com/en/US/products/ps10024/products_qanda_item09186a0080a359cc.shtml

    Reducing the Echo on the PSTN Line

    1.Make sure you are running the latest firmware. Everything should be set to factory defaults, or at least undo all the previous tweaking.
    2.Disable all the echo cancellation functions of your SPA3102. These settings can be found on line 1 and PSTN line tabs of your SPA3102.
    Echo Canc Enable = No
    Echo Canc Adaptive Enable = No
    Echo Supp Enable = No3.Remove devices connected to your phone line except the SPA3000. This includes all the extension cables and splitters. These can cause impedance problems which lead to echoes.
    4.Set the FXO port Impedance on the PSTN tab to 220+820||120nF, and set FXS Port Impedance to 220+820||115nF as a starting point.
    5.Look for Network Jitter Level on the PSTN Line tab and set it to low. Then, look for Jitter Buffer Adjustment and set it to disable. This reduces the delay across your SPA3000.
    Note: If you are using a poor quality VoIP service, go to the Line 1 tab and look for Network Jitter Level. Set it to low and set the Jitter Buffer Adjustment from up to down. However, if you are using a poor quality PSTN, set the Network Jitter Level to medium.

    6.Go to the PSTN Line under Audio Configuration. Look for Preferred Codec and set it to your preferred settings, then lock it in by setting the Use Pref Codec Only to yes. Adjust these settings if you are accessing your PSTN line via VoIP from a remote network. Then, go to Line 1 and set Preferred Codec with the same settings you set with PSTN Line. Under Preferred Codec Only set it to no. These settings reduce your latency and can make the echo less obvious or easier to catch with the echo canceller.
    7.Power cycle the SPA3000 by powering down the device. This sometimes fixes the problem especially after changing the physical phone wiring.
    8.Make some test calls and observe if you can hear an echo. If yes, the problem might be that you are sending too much power down the line and it gets reflected back somewhere as an echo. Even if you have good wiring but you are too close to the mouthpiece, you will still hear an echo. To resolve this, you need to increase the level of Gain by going to PSTN and look for SPA To PSTN Gain, then slowly adjust the level until you can clearly hear the person on the other line.
    Note: If you enable Echo Supp Enable, you will negate these parameters. The echo suppression is just an automatic gain control. It is recommended to keep it disabled.

    9.Make a test call to someone with a phone that works via the SPA's PSTN line, or call in to the PSTN line. If the remote party is hearing an echo, your phone might be loud and is experiencing feedback in the microphone. Lower the PSTN to SPA Gain until you are comfortable hearing the person on the other line. If the remote user can still hear an echo, try using a different phone plugged into the SPA. If this solves the problem, your phone might not be working properly, or there is an impedance mismatch between your phone and the SPA. Try changing the FXS Port Impedance to 600 on the Regional tab and change the FXO port impedance to 600 or global. If this does not help, change it back. The impedance will only affect what the remote party hears and will not help remove the echo you are hearing.
    10.After lowering the echo to a tolerable level, go back to the PSTN tab and enable Echo Can Enable by selecting Yes, OK. Check if the echo has improved. If the echo is tolerable at this level, leave the adaptive echo canceller off. You should have the echo level down to a level that can be filtered by the echo canceller. If you are using a sip device to talk through your PSTN line, you should probably do all the echo cancellation at that device and leave it switched off in the SPA.

    --------------------------------------------------------------------------------
    good luck

    andre
    Alma Québec Canada
     
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