What are your experiences with faxing through Asterisk to the PSTN? We are using g.711u as a codec, and are originating/terminating with Broadvox as well as through our own PSTN gateways. We have had some luck with incoming faxes coming into our network from Broadvox DIDs. They work 50% of the time. Not sure yet on PSTN incoming since nobody that is using FAX is in our local rate centers. Outgoing has been bad. It seems to work the best if the Sipura user agents have echo cancelation off, but we have to have echo cancelation on our outbound gateways or there is echo in the voice path. Faxing outbound works very rarely, and if it does, it usually can only send a page or two before we get the infamous "Poor line condition". Does anyone have a suitable FAX setup working? ---------------------------------------------------------------- This message was sent using IMP, the Internet Messaging Program.
> What are your experiences with faxing through Asterisk to the PSTN? > > We are using g.711u as a codec, and are originating/terminating withBroadvox as> well as through our own PSTN gateways. > > We have had some luck with incoming faxes coming into our network fromBroadvox> DIDs. They work 50% of the time. Not sure yet on PSTN incoming sincenobody> that is using FAX is in our local rate centers. > > Outgoing has been bad. It seems to work the best if the Sipura useragents have> echo cancelation off, but we have to have echo cancelation on our outbound > gateways or there is echo in the voice path. Faxing outbound works very > rarely, and if it does, it usually can only send a page or two before weget> the infamous "Poor line condition". > > Does anyone have a suitable FAX setup working?Our company's ourbound faxing (as well as the tpc.int fax server I run personally) goes through Asterisk with no problems to speak of. I recall the gain settings in Asterisk and on our Adit 600 channel bank needed some tuning, but it seems to work well now. The negotiated V.34 fax speeds are slightly lower than a direct PSTN hookup, but we're rarely in that much of a hurry ;-) As far as I know, echo cancelation routines/devices are meant to detect fax tones and shut themselves off. I saw this in action once ... while playing a recorded fax call back to a customer Asterisk turned off echo cancelation and my call was instantly very ... entertaining (for me at least - the call still sounded normal for the customer). As for using lines from Broadvox, even with g.711u codec, I would think all bets are off. The only reliable option for fax over VoIP is probably going to be t.38 (when it grows up). -Darren -- Darren Nickerson Senior Sales & Support Engineer iFax Solutions, Inc. www.ifax.com darren.nickerson@ifax.com +1.215.438.4638 x8106 +1.215.243.8335 (fax)
On 2004.07.28 19:33 matthew@txlink.net wrote:> What are your experiences with faxing through Asterisk to the PSTN?I have a setup that goes like this: PSTN <--> X100P <--> Asterisk <-uLAW-> SPA-2000 <--> HylaFAX 4.2.0 Asterisk reliably detects and routes incoming faxes to the appropriate station (one-line setup). I had to adjust some of the timings (lengthening them) in the HylaFAX modem configuration file, but other than that I have had no problem sending and receiving domestic faxes this way. I use ECM, so it compensates for most of the problems that can arise, but I do notice more difficulty in getting the fax through than when the HylaFAX modem is connected directly to the PSTN. However, I tried an international fax the other day, and it did not go through. I had to take Asterisk out of the loop. I am anxiously awaiting (and looking to help develop) Steve Underwood's (spandsp) pseudo-tty Class 1 modem for Asterisk.> We are using g.711u as a codec, and are originating/terminating with > Broadvox as > well as through our own PSTN gateways.You really must use a lossless codec, so g.711u (uLAW) is appropriate. However, you'll still probably have more success going through the local PSTN than through a VoIP carrier.> We have had some luck with incoming faxes coming into our network from > Broadvox > DIDs. They work 50% of the time. Not sure yet on PSTN incoming since > nobody > that is using FAX is in our local rate centers. > > Outgoing has been bad. It seems to work the best if the Sipura user > agents have > echo cancelation off,You must have echo cancellation off on that station.> but we have to have echo cancelation on our > outbound > gateways or there is echo in the voice path. Faxing outbound works > very > rarely, and if it does, it usually can only send a page or two before > we get > the infamous "Poor line condition". > > Does anyone have a suitable FAX setup working?I tend to believe that there are lots of us. That said, I think that doing it the old-fashioned way may be better for the time-being. So if you have dedicated fax lines, just run them directly to the fax device rather than through a PBX. Lee.
matthew@txlink.net wrote:>What are your experiences with faxing through Asterisk to the PSTN? > >We are using g.711u as a codec, and are originating/terminating with Broadvox as >well as through our own PSTN gateways. > >We have had some luck with incoming faxes coming into our network from Broadvox >DIDs. They work 50% of the time. Not sure yet on PSTN incoming since nobody >that is using FAX is in our local rate centers. > >Outgoing has been bad. It seems to work the best if the Sipura user agents have >echo cancelation off, but we have to have echo cancelation on our outbound >gateways or there is echo in the voice path. Faxing outbound works very >rarely, and if it does, it usually can only send a page or two before we get >the infamous "Poor line condition". > >Does anyone have a suitable FAX setup working? >Using G.711 u or A may work, but don't count on it. Take a look at http://www.opencall.org/faq Regards, Steve