Re: [Asterisk-Users] Clarification on Fax capability?
Wondering if someone (Steve?) can clarify something form me. I think the recent soho fax solution? thread has mixed things up for me. - Is it possible to get reliable fax reception using a Zaptel FXO interface connected to a standard POTS line and a fax machine connected to station interface? - Is it possible to reliably send outboud faxes in the reverse direction? I understand the issues with fax over VoIP. I just want to handle faxes here in my small office without dedicating a line to the machine. The function of faxing over a zaptel interface (eg, x100p, tdm) is not consistent from one implementation to another, regardless of whether your using Stable or Head. The two basic approaches that are commonly discussed on the list are: 1) using Steve's spandsp patches to intercept faxes, creating an *.tif file that can be emailed and viewed outside of *, and, 2) simply switching a fax call through * to a tip/ring interface of some sort that has an attached traditional fax machine. Option #2 works in many cases if the incoming fax call is handled by the g711 codec. The fax call is no different then receiving any other call, however any analog-based modem tones passed through a digital interface (eg, asterisk) are _not_ reproduced reliably. The higher the modem speed, the greater chance of distorting the analog signal tones, and the greater the chance of fax not working at all. (You'll find the older-slower modems will work better then newer-faster fax machines. Essentially, modems that operate at 9600 baud or slower are more reliable then anything faster.) Option #1 works in some cases with Digitum fxo cards, however something close to 50% (or more) implementations fail to work in any form of reliable way. The issuse seems to be related to funcky things happening with the zaptel/wctdm drivers that cause missed pcm frames (or slips) between the digium cards and the asterisk code. Missed or slipped frames will negatively impact any modem-based communications, including fax machines. Steve has received recent reports (#1) that suggest that outgoing faxes are now failing at a significant rate indicating that something has changed in the zaptel/wctdm drivers negatively impacting such calls. No one (to the best of my knowledge) has complained about the drivers impacting voice, however small numbers of missed or slipped frames are generally not noticed (or are not that objectionable). If you dig through the archives, you'll probably notice a fair number of folks having issues with the digium x100p/tdm cards that revolve around interrupt latency and/or pci bus problems. Those issues tend to be associated with echo and many have found that swapping motherboards corrects the problem. But, no one (to the best of my knowledge) has ever discovered why swapping motherboards corrects the problem; they just know that it does. Likewise, no one has assembled a list of motherboards that work simply because it is very difficult to determine motherboard models when companies like Dell HP do not publish who's board they actually use in their products (not to mention that some system vendors have different boards in the exact same system models). We do know that processor speed, number of processors, amount of ram, etc, has little or no impact on the issues. Some have noted that moving from a P4 to a slower speed P3 processor has corrected the issues, but those type changes essentially have hundreds of other changes along with that switch. Its unlikely the actual processor switch had anything to do with it; more likely is that changes that came along in the form of a different pci bus structure actually improved it (or something like that). So, the best guess (today) is that a driver or hardware problem (pci chip set) exists between the digium cards and the underlying motherboard that negatively impacts the reliable transfer of data from those cards to asterisk code, thus impacting voice (echo) and fax (modem signals). It doesn't help that the drivers and cards are essentially considered digium property and that all support should come from that source. Opening a trouble ticket with digium (on this particular issue) tends to go directly into a black hole. Some of that is likely due to the sophistication (and/or lack of understanding) of those responsible for supporting those products since one has to fully understand how to deal with specific hardware (eg, chip sets), kernel drivers, asterisk code, etc. If you try to analyze the code in zaptel and wctdm you'll understand why that is. Bottom line is the tdm card drivers seem to be just okay for voice, but no where near reliable or even predictable for fax. That's based on cvs head and spandsp-pre9 code as of this morning. ___ Asterisk-Users mailing list Asterisk-Users@lists.digium.com http://lists.digium.com/mailman/listinfo/asterisk-users To UNSUBSCRIBE or update
Re: [Asterisk-Users] Clarification on Fax capability?
On Tue, February 15, 2005 7:48 am, Rich Adamson said: 2) simply switching a fax call through * to a tip/ring interface of some sort that has an attached traditional fax machine. Does the codec issue with #2 still apply if the incoming fax call is on a Zaptel FXO interface? Is the codec used when connecting two channels on the same zaptel card or does the native bridg[ing] bypass that? Thanks for the info. Paul -- Paul A. DugasDugas Enterprises, LLC [EMAIL PROTECTED]1711 Indian Ridge Drive p:404-932-1355 f:770-516-4841 Woodstock, GA 30189-6856 USA ___ Asterisk-Users mailing list Asterisk-Users@lists.digium.com http://lists.digium.com/mailman/listinfo/asterisk-users To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users
Re: [Asterisk-Users] Clarification on Fax capability?
On Tue, February 15, 2005 7:48 am, Rich Adamson said: 2) simply switching a fax call through * to a tip/ring interface of some sort that has an attached traditional fax machine. Does the codec issue with #2 still apply if the incoming fax call is on a Zaptel FXO interface? Is the codec used when connecting two channels on the same zaptel card or does the native bridg[ing] bypass that? Funny that you should ask. I just finished testing it using the faxdetect=incoming method, redirecting the call to a Cisco ata186. The incoming call arrived on a TDM fxo port. Received the fax header, but the remainder of the page was blank. The sender received a message indicating a failure. Best guess... the tdm driver problem is impacting the ability to send the fax tones reliably even with g711. Its very likely to be the interrupt latency and/or pci bus problem on this particular system. ___ Asterisk-Users mailing list Asterisk-Users@lists.digium.com http://lists.digium.com/mailman/listinfo/asterisk-users To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users
Re: [Asterisk-Users] Clarification on Fax capability?
I've been trying this for a while and I have been unable to get a reliable connection betwen two Zaptel FXS interfaces, so the bridging does afect data transfer. Anybody got some tunning tips to get this to work ? I'm using a dual PIII with a ServerWorks Chipset, two TDM cards (8xFXS) and a Fritz Capi to connect to my telecom provider. I can send faxes with some success, but receiving rate of success is less than 30%. Fax information for Asterisk is difficult to come by is everybody using spandsp's way ? Thx Pedro Caria On 15/fev/2005, at 15:05, Rich Adamson wrote: On Tue, February 15, 2005 7:48 am, Rich Adamson said: 2) simply switching a fax call through * to a tip/ring interface of some sort that has an attached traditional fax machine. Does the codec issue with #2 still apply if the incoming fax call is on a Zaptel FXO interface? Is the codec used when connecting two channels on the same zaptel card or does the native bridg[ing] bypass that? Funny that you should ask. I just finished testing it using the faxdetect=incoming method, redirecting the call to a Cisco ata186. The incoming call arrived on a TDM fxo port. Received the fax header, but the remainder of the page was blank. The sender received a message indicating a failure. Best guess... the tdm driver problem is impacting the ability to send the fax tones reliably even with g711. Its very likely to be the interrupt latency and/or pci bus problem on this particular system. ___ Asterisk-Users mailing list Asterisk-Users@lists.digium.com http://lists.digium.com/mailman/listinfo/asterisk-users To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users ___ Asterisk-Users mailing list Asterisk-Users@lists.digium.com http://lists.digium.com/mailman/listinfo/asterisk-users To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users
[Asterisk-Users] Clarification on Fax capability?
Wondering if someone (Steve?) can clarify something form me. I think the recent soho fax solution? thread has mixed things up for me. - Is it possible to get reliable fax reception using a Zaptel FXO interface connected to a standard POTS line and a fax machine connected to station interface? - Is it possible to reliably send outboud faxes in the reverse direction? I understand the issues with fax over VoIP. I just want to handle faxes here in my small office without dedicating a line to the machine. Thanks in advance. -- Paul A. DugasDugas Enterprises, LLC [EMAIL PROTECTED]1711 Indian Ridge Drive p:404-932-1355 f:770-516-4841 Woodstock, GA 30189-6856 USA ___ Asterisk-Users mailing list Asterisk-Users@lists.digium.com http://lists.digium.com/mailman/listinfo/asterisk-users To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users
Re: [Asterisk-Users] Clarification on Fax capability?
Wondering if someone (Steve?) can clarify something form me. I think the recent soho fax solution? thread has mixed things up for me. ditto. :-) Are there any issues having Asterisk and HylaFax/smb share on the same server? Using FXO ports? (not isdn) what about the applications sharing a FXO port? Or having dedicated ports? ___ Asterisk-Users mailing list Asterisk-Users@lists.digium.com http://lists.digium.com/mailman/listinfo/asterisk-users To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users
