Re: [asterisk-users] Disabling Echo Cancellation on a per Call basis
Hello, just want to bring this question up again. Is someone able to tell me, yes you can disable echo can on a per call basis and it is done this way, or not it is not possible, go away ... If it is not possible, why is that so ? Is there really no need to do this and i am totally mistaken? Generally receiving faxes works fine, but sometimes they break and i assume i might have something to do with echo can. Kind Regards, Tobias Tobias Wolf schrieb: Olivier schrieb: 2009/2/10 Tobias Wolf tobias.w...@evision.de mailto:tobias.w...@evision.de Hello all, i was just made aware on the Bristuff-Mailing list, that it is possible to disable echo cancellation per dialplan application. This comes in very handy, for terminating faxes. But the application seems only to be existing in the bristuff patches. Does there exist a solution for Asterisk 1.6.0.3 Digium Wildcard TE110P T1/E1 DAHDI Version: 2.1.0.3 Echo Canceller: MG2 without any Bristuff? At the Moment i have fax detection enabled. Do you mean a given DID receives voice or fax calls ? If positive, which app is detecting faxes ? Since i have a dedicated DID for fax calls, i don't really need the fax detection. For this number i simply start the ReceiveFAX-Application and have some voodoo around it to name the file correctly. But if i do this, and look into the channel information from Dahdi i see that the fax handled flag is set to no. And this seems wrong to me. I have the feeling that the percentage of failed faxes is higher is this flag is set to no (or false, can't remember) ... Since i have a PRI connected to my Asterisk, i use the built-in fax detection of DAHDI. I have enabled it for incoming fax calls, in chan_dahdi.conf faxdetect=incoming The incoming call is answered and with an included Wait(4) the fax is detected and switched to the fax extension, where the ReceiveFAX-App is executed. Now the fax handled flag is set to yes and i am able to receive most of the fax calls. But i have massive problems receiving fax calls from certain people, especially from UK (i am in germany). I am not quite sure, if the echo canceller is automatically disabled if DAHDI knows that the call is a fax and the channel info doesn't indicate otherwise, since it says that echo canceller is active even if it says that it handles an fax. This is the reason why i was so happy to hear, that there seems to be the option to control the echo canceller with an dialplan app. But since this seems to be an Bristuff-only feature i am a little bit stuck. Kind regards, ___ -- Bandwidth and Colocation Provided by http://www.api-digital.com -- asterisk-users mailing list To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users
Re: [asterisk-users] Disabling Echo Cancellation on a per Call basis
Tobias Wolf wrote: If it is not possible, why is that so ? Is there really no need to do this and i am totally mistaken? This is generally true. Any standards-compliant FAX machine or modem will generate a CED tone during the beginning of the call process, and any standards compliant echo canceler (including the ones in Zaptel/DAHDI) will respond to this tone by disabling the echo canceler. With Zaptel/DAHDI and a software echo canceler, you can see the evidence of this by watching the kernel message log for messages of the form 'Disabled echo canceler because of tone (..) on channel If a hardware echo canceler is in use, there won't be any messages generated, but it is still happening. Generally receiving faxes works fine, but sometimes they break and i assume i might have something to do with echo can. Unfortunately that is not likely to be the cause of your problems. -- Kevin P. Fleming Digium, Inc. | Director of Software Technologies 445 Jan Davis Drive NW - Huntsville, AL 35806 - USA skype: kpfleming | jabber: kpflem...@digium.com Check us out at www.digium.com www.asterisk.org ___ -- Bandwidth and Colocation Provided by http://www.api-digital.com -- asterisk-users mailing list To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users
Re: [asterisk-users] Disabling Echo Cancellation on a per Call basis
Hi Kevin, Kevin P. Fleming schrieb: Tobias Wolf wrote: If it is not possible, why is that so ? Is there really no need to do this and i am totally mistaken? This is generally true. Any standards-compliant FAX machine or modem will generate a CED tone during the beginning of the call process, and any standards compliant echo canceler (including the ones in Zaptel/DAHDI) will respond to this tone by disabling the echo canceler. With Zaptel/DAHDI and a software echo canceler, you can see the evidence of this by watching the kernel message log for messages of the form 'Disabled echo canceler because of tone (..) on channel Does this only take place if fax detection is enabled in DAHDI or is it something that happens everytime a CED tone is send over the line? Since i have only deticated fax lines, i like to get rid of the fax detection for that i need to add an Wait(4) to the dialplan, after Answer(). Unfortunatly my Linux Machine seems not to log messages from DAHDI. I have looked into /var/log/kern.log There are messages from the kernel module like; Feb 11 17:38:12 officepbx kernel: wcte1xxp: Setting yellow alarm Feb 11 17:38:21 officepbx kernel: wcte1xxp: Clearing yellow alarm But no messages about echo can. Maybe i am missing configuration for the kernel module to enable logging ? Generally receiving faxes works fine, but sometimes they break and i assume i might have something to do with echo can. Unfortunately that is not likely to be the cause of your problems. Well, this may be the case ... But thanks anyway for your helpful informations, they help me a lot to get a better understanding. Cheers, -- Tobias Wolf ___ -- Bandwidth and Colocation Provided by http://www.api-digital.com -- asterisk-users mailing list To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users
Re: [asterisk-users] Disabling Echo Cancellation on a per Call basis
Tobias Wolf wrote: Does this only take place if fax detection is enabled in DAHDI or is it something that happens everytime a CED tone is send over the line? FAX detection is not done in DAHDI, it's done in chan_dahdi (in Asterisk). CED detection is done in the echo canceler itself, so it is completely independent of Asterisk (or any application, for that matter). Correctly responding to CED is something that an echo canceler must do just to be compliant with various specifications. Unfortunatly my Linux Machine seems not to log messages from DAHDI. I have looked into /var/log/kern.log There are messages from the kernel module like; Feb 11 17:38:12 officepbx kernel: wcte1xxp: Setting yellow alarm Feb 11 17:38:21 officepbx kernel: wcte1xxp: Clearing yellow alarm But no messages about echo can. Maybe i am missing configuration for the kernel module to enable logging ? It's logged as a LOG_NOTICE message and is always generated, unless DAHDI was built with NO_ECHOCAN_DISABLE defined, which would be uncommon. However, /var/log/kern.log on your system might be only from the boot process. Have you checked 'dmesg' as the system is running? -- Kevin P. Fleming Digium, Inc. | Director of Software Technologies 445 Jan Davis Drive NW - Huntsville, AL 35806 - USA skype: kpfleming | jabber: kpflem...@digium.com Check us out at www.digium.com www.asterisk.org ___ -- Bandwidth and Colocation Provided by http://www.api-digital.com -- asterisk-users mailing list To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users
Re: [asterisk-users] Disabling Echo Cancellation on a per Call basis
Kevin P. Fleming schrieb: Tobias Wolf wrote: Does this only take place if fax detection is enabled in DAHDI or is it something that happens everytime a CED tone is send over the line? FAX detection is not done in DAHDI, it's done in chan_dahdi (in Asterisk). CED detection is done in the echo canceler itself, so it is completely independent of Asterisk (or any application, for that matter). Correctly responding to CED is something that an echo canceler must do just to be compliant with various specifications. Alright, understood. Unfortunatly my Linux Machine seems not to log messages from DAHDI. I have looked into /var/log/kern.log There are messages from the kernel module like; Feb 11 17:38:12 officepbx kernel: wcte1xxp: Setting yellow alarm Feb 11 17:38:21 officepbx kernel: wcte1xxp: Clearing yellow alarm But no messages about echo can. Maybe i am missing configuration for the kernel module to enable logging ? It's logged as a LOG_NOTICE message and is always generated, unless DAHDI was built with NO_ECHOCAN_DISABLE defined, which would be uncommon. However, /var/log/kern.log on your system might be only from the boot process. Have you checked 'dmesg' as the system is running? Have done that, no messages appear while receiving a fax. I know that i have seen such messages before the upgrade. I have another asterisk server which is bristuffed, and there i can see this message with 'dmesg'. I am absolutly positive that DAHDI was not built with NO_ECHOCAN_DISABLE, since i have only downloaded the package and done a 'make; make install' without touching anything of the source code. By the way, i am using DAHDI-linux 2.1.0.3. Regards -- Tobias Wolf ___ -- Bandwidth and Colocation Provided by http://www.api-digital.com -- asterisk-users mailing list To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users
Re: [asterisk-users] Disabling Echo Cancellation on a per Call basis
Tobias Wolf wrote: I am absolutly positive that DAHDI was not built with NO_ECHOCAN_DISABLE, since i have only downloaded the package and done a 'make; make install' without touching anything of the source code. By the way, i am using DAHDI-linux 2.1.0.3. Can you post your /etc/dahdi/system.conf? -- Kevin P. Fleming Digium, Inc. | Director of Software Technologies 445 Jan Davis Drive NW - Huntsville, AL 35806 - USA skype: kpfleming | jabber: kpflem...@digium.com Check us out at www.digium.com www.asterisk.org ___ -- Bandwidth and Colocation Provided by http://www.api-digital.com -- asterisk-users mailing list To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users
Re: [asterisk-users] Disabling Echo Cancellation on a per Call basis
Kevin P. Fleming schrieb: Tobias Wolf wrote: I am absolutly positive that DAHDI was not built with NO_ECHOCAN_DISABLE, since i have only downloaded the package and done a 'make; make install' without touching anything of the source code. By the way, i am using DAHDI-linux 2.1.0.3. Can you post your /etc/dahdi/system.conf? Sure, here you are: See Attachment ... # # DAHDI Configuration File # # This file is parsed by the DAHDI Configurator, dahdi_cfg # # Span Configuration # ^^ # First come the span definitions, in the format # # span=span num,timing source,line build out (LBO),framing,coding[,yellow] # # All T1/E1/BRI spans generate a clock signal on their transmit side. The # timing source parameter determines whether the clock signal from the far # end of the T1/E1/BRI is used as the master source of clock timing. If it is, our # own clock will synchronise to it. T1/E1/BRI connected directly or indirectly to # a PSTN provider (telco) should generally be the first choice to sync to. The # PSTN will never be a slave to you. You must be a slave to it. # # Choose 1 to make the equipment at the far end of the E1/T1/BRI link the preferred # source of the master clock. Choose 2 to make it the second choice for the master # clock, if the first choice port fails (the far end dies, a cable breaks, or # whatever). Choose 3 to make a port the third choice, and so on. If you have, say, # 2 ports connected to the PSTN, mark those as 1 and 2. The number used for each # port should be different. # # If you choose 0, the port will never be used as a source of timing. This is # appropriate when you know the far end should always be a slave to you. If # the port is connected to a channel bank, for example, you should always be # its master. Likewise, BRI TE ports should always be configured as a slave. # Any number of ports can be marked as 0. # # Incorrect timing sync may cause clicks/noise in the audio, poor quality or failed # faxes, unreliable modem operation, and is a general all round bad thing. # # The line build-out (or LBO) is an integer, from the following table: # # 0: 0 db (CSU) / 0-133 feet (DSX-1) # 1: 133-266 feet (DSX-1) # 2: 266-399 feet (DSX-1) # 3: 399-533 feet (DSX-1) # 4: 533-655 feet (DSX-1) # 5: -7.5db (CSU) # 6: -15db (CSU) # 7: -22.5db (CSU) # # If the span is a BRI port the line build-out is not used and should be set # to 0. # # framing:: # one of 'd4' or 'esf' for T1 or 'cas' or 'ccs' for E1. Use 'ccs' for BRI. # 'd4' could be referred to as 'sf' or 'superframe' # # coding:: # one of 'ami' or 'b8zs' for T1 or 'ami' or 'hdb3' for E1. Use 'ami' for # BRI. # # * For E1 there is the optional keyword 'crc4' to enable CRC4 checking. # * If the keyword 'yellow' follows, yellow alarm is transmitted when no # channels are open. # #span=1,0,0,esf,b8zs #span=2,1,0,esf,b8zs #span=3,0,0,ccs,hdb3,crc4 # # DOKOM span=1,1,0,ccs,hdb3,crc4,yellow bchan=1-15 dchan=16 bchan=17-31 # Dynamic Spans # ^ # Next come the dynamic span definitions, in the form: # # dynamic=driver,address,numchans,timing # # Where driver is the name of the driver (e.g. eth), address is the # driver specific address (like a MAC for eth), numchans is the number # of channels, and timing is a timing priority, like for a normal span. # use 0 to not use this as a timing source, or prioritize them as # primary, secondard, etc. Note that you MUST have a REAL DAHDI device # if you are not using external timing. # # dynamic=eth,eth0/00:02:b3:35:43:9c,24,0 # # If a non-zero timing value is used, as above, only the last span should # have the non-zero value. # # Channel Configuration # ^ # Next come the definitions for using the channels. The format is: # device=channel list # # Valid devices are: # # em:: # Channel(s) are signalled using EM signalling (specific # implementation, such as Immediate, Wink, or Feature Group D # are handled by the userspace library). # fxsls:: # Channel(s) are signalled using FXS Loopstart protocol. # fxsgs:: # Channel(s) are signalled using FXS Groundstart protocol. # fxsks:: # Channel(s) are signalled using FXS Koolstart protocol. # fxols:: # Channel(s) are signalled using FXO Loopstart protocol. # fxogs:: # Channel(s) are signalled using FXO Groundstart protocol. # fxoks:: # Channel(s) are signalled using FXO Koolstart protocol. # sf:: # Channel(s) are signalled using in-band single freq tone. # Syntax as follows: # # channel# = sf:rxfreq,rxbw,rxflag,txfreq,txlevel,txflag # # rxfreq is rx tone freq in Hz, rxbw is rx notch (and decode) # bandwith in hz (typically 10.0), rxflag is either 'normal' or # 'inverted', txfreq is tx tone freq in hz, txlevel is tx tone # level in dbm, txflag is either 'normal' or 'inverted'. Set # rxfreq or txfreq to 0.0 if that tone is not desired. # # unused:: # No signalling is performed, each channel in the list remains
Re: [asterisk-users] Disabling Echo Cancellation on a per Call basis
Tobias Wolf wrote: Sure, here you are: See Attachment ... Well, that looks perfectly normal. I'm not sure what to tell you, other than that your system might be configured (via klogd) to suppress NOTICE-level kernel messages after boot time or something like that. If you are comfortable editing code, you can find the 'Disabled echo...' line in drivers/dahdi/dahdi-base.c and change the KERN_NOTICE to KERN_WARNING or KERN_ERROR to see if that makes it appear. -- Kevin P. Fleming Digium, Inc. | Director of Software Technologies 445 Jan Davis Drive NW - Huntsville, AL 35806 - USA skype: kpfleming | jabber: kpflem...@digium.com Check us out at www.digium.com www.asterisk.org ___ -- Bandwidth and Colocation Provided by http://www.api-digital.com -- asterisk-users mailing list To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users
[asterisk-users] Disabling Echo Cancellation on a per Call basis
Hello all, i was just made aware on the Bristuff-Mailing list, that it is possible to disable echo cancellation per dialplan application. This comes in very handy, for terminating faxes. But the application seems only to be existing in the bristuff patches. Does there exist a solution for Asterisk 1.6.0.3 Digium Wildcard TE110P T1/E1 DAHDI Version: 2.1.0.3 Echo Canceller: MG2 without any Bristuff? At the Moment i have fax detection enabled. If a fax comes in a see that fax handling on the channel is set to true, but echo cancellation is also on. This makes problems with low quality fax calls, they break nearly 100%. I am guessing that disabling echo can might improve this. Kind Regards, -- Tobias Wolf ___ -- Bandwidth and Colocation Provided by http://www.api-digital.com -- asterisk-users mailing list To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users
Re: [asterisk-users] Disabling Echo Cancellation on a per Call basis
2009/2/10 Tobias Wolf tobias.w...@evision.de Hello all, i was just made aware on the Bristuff-Mailing list, that it is possible to disable echo cancellation per dialplan application. This comes in very handy, for terminating faxes. But the application seems only to be existing in the bristuff patches. Does there exist a solution for Asterisk 1.6.0.3 Digium Wildcard TE110P T1/E1 DAHDI Version: 2.1.0.3 Echo Canceller: MG2 without any Bristuff? At the Moment i have fax detection enabled. Do you mean a given DID receives voice or fax calls ? If positive, which app is detecting faxes ? If a fax comes in a see that fax handling on the channel is set to true, but echo cancellation is also on. This makes problems with low quality fax calls, they break nearly 100%. I am guessing that disabling echo can might improve this. Kind Regards, -- Tobias Wolf ___ -- Bandwidth and Colocation Provided by http://www.api-digital.com -- asterisk-users mailing list To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users ___ -- Bandwidth and Colocation Provided by http://www.api-digital.com -- asterisk-users mailing list To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users
Re: [asterisk-users] Disabling Echo Cancellation on a per Call basis
Olivier schrieb: 2009/2/10 Tobias Wolf tobias.w...@evision.de mailto:tobias.w...@evision.de Hello all, i was just made aware on the Bristuff-Mailing list, that it is possible to disable echo cancellation per dialplan application. This comes in very handy, for terminating faxes. But the application seems only to be existing in the bristuff patches. Does there exist a solution for Asterisk 1.6.0.3 Digium Wildcard TE110P T1/E1 DAHDI Version: 2.1.0.3 Echo Canceller: MG2 without any Bristuff? At the Moment i have fax detection enabled. Do you mean a given DID receives voice or fax calls ? If positive, which app is detecting faxes ? Since i have a dedicated DID for fax calls, i don't really need the fax detection. For this number i simply start the ReceiveFAX-Application and have some voodoo around it to name the file correctly. But if i do this, and look into the channel information from Dahdi i see that the fax handled flag is set to no. And this seems wrong to me. I have the feeling that the percentage of failed faxes is higher is this flag is set to no (or false, can't remember) ... Since i have a PRI connected to my Asterisk, i use the built-in fax detection of DAHDI. I have enabled it for incoming fax calls, in chan_dahdi.conf faxdetect=incoming The incoming call is answered and with an included Wait(4) the fax is detected and switched to the fax extension, where the ReceiveFAX-App is executed. Now the fax handled flag is set to yes and i am able to receive most of the fax calls. But i have massive problems receiving fax calls from certain people, especially from UK (i am in germany). I am not quite sure, if the echo canceller is automatically disabled if DAHDI knows that the call is a fax and the channel info doesn't indicate otherwise, since it says that echo canceller is active even if it says that it handles an fax. This is the reason why i was so happy to hear, that there seems to be the option to control the echo canceller with an dialplan app. But since this seems to be an Bristuff-only feature i am a little bit stuck. Kind regards, -- Tobias Wolf ___ -- Bandwidth and Colocation Provided by http://www.api-digital.com -- asterisk-users mailing list To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users
