Re: [WISPA] OT Fax over Voip
You don't need vlans but helps in keeping voice and data separate. but what is needed is qos. Make sure that is setup correctly. Even with vlans you should have it. Leon Sent from my iPhone On Apr 2, 2014, at 9:03 AM, wi...@mncomm.com wrote: OK, I will. Right now its on my remote techs bench with a Cat5e cable and a switch between the 2 devices. Where this will be going is a farmers elevator site 150 feet between the 2 buildings using UBNT NSM5 radios, excellent quality. Right now they are using 5 VoIP NEC phones at the remote site, plus the same link is carrying their data needs as well, for 5 PCs. I didn’t build separate VLANs as it is a very small network. Regardless I cannot get these to work 10 feet to each other over cable. Voice works great. I will have my tech put together what he has done. He has several hours into it. Usually we wouldn’t dive into stuff too deep, but this customer also hosts a major site for us using their grain leg thanks heith -Original Message- From: Nathan Anderson Sent: Tuesday, April 01, 2014 8:52 PM To: 'WISPA General List' Subject: Re: [WISPA] OT Fax over Voip On Monday, March 31, 2014 7:04 AM, wi...@mncomm.com wrote: So, the scenario would be the CO goes into a gateway device to convert to digital, goes over the LAN to the other gateway device. That device hooks up to the fax machine. If someone has done this before can you share the products you may have used? The products we have say they will work this way, but no luck, just voice transmission. I may have a bad device as well. If you are talking about a private point-to-point wireless link shot between two buildings across a parking lot or whatever, with excellent link quality characteristics and low jitter and latency, there is no reason that I can think of why moving the fax machine over wouldn't just work. Perhaps you could share with us the following: 1. Model of the Grandstream gateways in question. 2. How you have the gateways configured (e.g., codec being used and such). 3. What equipment you are using to do the wireless shot. 4. Average throughput, latency, and jitter across that link. 5. Whether the link is for phone use only, or is combined voice and data. 6. ...if combined, whether any kind of QoS is being employed to promote voice transmission ahead of data. ...and, most importantly... 7. What exactly happens when you try to send or receive a fax over the gateway devices. A vague it doesn't work description never helped anybody solve anything. :-) Give us details. How does it fail, exactly? How far along does it get? Is it able to transmit a partial page and then the connection drops? Or can it not even complete the handshake with the other fax machine? If it works for voice, I very much doubt you have a bad device, unless it is a software/firmware issue on the device(s). If the device was physically bad, I suspect the defect would present itself in other ways as well. General things to try out and to look out for: If you are using some fancy, efficient voice codec like G.729, turn that crap off. Limit both gateways to negotiate G.711u with each other only. If they have a T.38 option, make sure it is either enabled on both sides, or disabled on both sides...if there is a mismatch, some SIP stacks behave very badly if/when their re-INVITE to T.38 is rejected by the other peer. If the gateway devices support T.38 and it happens to be enabled, try turning it off. The T.38 spec is so vague as to often be useless, and there can be interop problems even between two identical devices (I swear that sometimes vendors don't test their own products...it's infuriating). And on a private, short-haul link like that, I would sure think that using G.711u PCM for both voice and fax transmission would be sufficient and pose no problems. On the other hand, if latency and jitter are sometimes a problem and the quality of the link is in doubt, and you haven't been using T.38, then by all means give T.38 a try, assuming your Grandstream devices can act as T.38 gateways (it's not enough for them to have T.38 passthrough support, they must have GATEWAY functionality). Once you finally get past all of the interop issues, T.38 really can work magic for FoIP on uncontrolled IP links. If you are using T.38 (or, heck, even if you aren't using T.38), try forcibly lowering the maximum modulation rate that their fax machine will attempt to handshake to the other side with. It is still (sadly) incredibly common for most production T.38 implementations these days to be based off of version 0, which does not include support for gatewaying V.34, only V.17. If they have a Super G3 fax machine, the T.38 gateway feature should in theory just ignore the handshake and not even engage and try to re-INVITE to T.38, but you never know...could be buggy. Or if you aren't
Re: [WISPA] OT Fax over Voip
What I of for faxing is use vitelitys fax service. It comes in to my email as PDF case closed. Outbound I got fax working from my machine or I send it via the Vitelity fax portal. Sent from my iPhone On Apr 2, 2014, at 6:18 PM, wi...@mncomm.com wrote: I havent got my tech to log what he has done so far. Lines will connect to and from remote fax machines, no handshake apparently, no talky over the devices. I will be more descriptive shortly. Sucks that he is four hours away and a rookie compared to me with telephony, not that I am much better haha -Original Message- From: Fred Goldstein Sent: Wednesday, April 02, 2014 5:08 PM To: wireless@wispa.org Subject: Re: [WISPA] OT Fax over Voip On 4/2/2014 5:24 PM, Nathan Anderson wrote: On Wednesday, April 02, 2014 6:55 AM, Fred Goldstein wrote: But in addition to that, I STRONGLY recommend a separate VLAN for the voice-grade channels. With priority, or reserved bandwidth. TCP/IP in normal operation manages its flow rate by having packets thrown away; that's why the 1G LAN port on your PC doesn't blast a whole file at 1G into a 2M link. It uses packet loss as a signal. TCP applications retransmit and actual human voice is intelligible with some gaps, but modems, including fax, are very unhappy. Do note that RTP is implemented over UDP, not TCP, so in VoIP, a dropped audio packet is a lost audio packet, not a delayed or even out-of-order audio packet (although those other two things can happen...they just aren't a result of retransmits, or at least not a retransmit initiated by Layer 4). I guess my grammar was a bit rough there! So you're of course right. TCP applications retransmit. (period) Actual human voice (which doesn't retransmit, as it can't wait) is intelligible some gaps. Modes, however, including fax, are very unhappy with gaps. And stressing Nathan's previous note (*what* doesn't work?), this may be one of those *rare* occasions when a video (YouTube anyone?) might actually help. Although the audio alone is more important. If we could (see and) hear the call being dialed by the originating fax, hear what the ring sequence sounded like, and heard the response, with the speaker belching the CNG tone all along, it might help identify the problem. But really, fax and VoIP don't get along very well unless you really tune the VoIP network up to support it. And I know how some faxes are picky. My office fax line sat here virtually unused for years, but my wife needs to receive faxes regularly. Her fax is on a Comcast PacketCable (they call it VoIP but it's really managed VuIP) line that is shared with her office phone and answering machine. My fax (both are Brothers) can send hers a fax. The answering machine gives its spiel, starts to listen, then the fax hears CNG and cuts off the answering machine and sends modem tones. Just like it's supposed to work. But the fancy new fax server system at the courthouse just won't send to it. (Nor will some sizeable fraction of other machines.) It will send to mine, which isn't shared with an answering machine, but not one that is. Picky picky. Fax is like that. -- Fred R. Goldstein k1io fred at interisle.net Interisle Consulting Group +1 617 795 2701 ___ Wireless mailing list Wireless@wispa.org http://lists.wispa.org/mailman/listinfo/wireless ___ Wireless mailing list Wireless@wispa.org http://lists.wispa.org/mailman/listinfo/wireless ___ Wireless mailing list Wireless@wispa.org http://lists.wispa.org/mailman/listinfo/wireless
Re: [WISPA] OT Fax over Voip
OK, I will. Right now its on my remote techs bench with a Cat5e cable and a switch between the 2 devices. Where this will be going is a farmers elevator site 150 feet between the 2 buildings using UBNT NSM5 radios, excellent quality. Right now they are using 5 VoIP NEC phones at the remote site, plus the same link is carrying their data needs as well, for 5 PCs. I didn’t build separate VLANs as it is a very small network. Regardless I cannot get these to work 10 feet to each other over cable. Voice works great. I will have my tech put together what he has done. He has several hours into it. Usually we wouldn’t dive into stuff too deep, but this customer also hosts a major site for us using their grain leg thanks heith -Original Message- From: Nathan Anderson Sent: Tuesday, April 01, 2014 8:52 PM To: 'WISPA General List' Subject: Re: [WISPA] OT Fax over Voip On Monday, March 31, 2014 7:04 AM, wi...@mncomm.com wrote: So, the scenario would be the CO goes into a gateway device to convert to digital, goes over the LAN to the other gateway device. That device hooks up to the fax machine. If someone has done this before can you share the products you may have used? The products we have say they will work this way, but no luck, just voice transmission. I may have a bad device as well. If you are talking about a private point-to-point wireless link shot between two buildings across a parking lot or whatever, with excellent link quality characteristics and low jitter and latency, there is no reason that I can think of why moving the fax machine over wouldn't just work. Perhaps you could share with us the following: 1. Model of the Grandstream gateways in question. 2. How you have the gateways configured (e.g., codec being used and such). 3. What equipment you are using to do the wireless shot. 4. Average throughput, latency, and jitter across that link. 5. Whether the link is for phone use only, or is combined voice and data. 6. ...if combined, whether any kind of QoS is being employed to promote voice transmission ahead of data. ...and, most importantly... 7. What exactly happens when you try to send or receive a fax over the gateway devices. A vague it doesn't work description never helped anybody solve anything. :-) Give us details. How does it fail, exactly? How far along does it get? Is it able to transmit a partial page and then the connection drops? Or can it not even complete the handshake with the other fax machine? If it works for voice, I very much doubt you have a bad device, unless it is a software/firmware issue on the device(s). If the device was physically bad, I suspect the defect would present itself in other ways as well. General things to try out and to look out for: If you are using some fancy, efficient voice codec like G.729, turn that crap off. Limit both gateways to negotiate G.711u with each other only. If they have a T.38 option, make sure it is either enabled on both sides, or disabled on both sides...if there is a mismatch, some SIP stacks behave very badly if/when their re-INVITE to T.38 is rejected by the other peer. If the gateway devices support T.38 and it happens to be enabled, try turning it off. The T.38 spec is so vague as to often be useless, and there can be interop problems even between two identical devices (I swear that sometimes vendors don't test their own products...it's infuriating). And on a private, short-haul link like that, I would sure think that using G.711u PCM for both voice and fax transmission would be sufficient and pose no problems. On the other hand, if latency and jitter are sometimes a problem and the quality of the link is in doubt, and you haven't been using T.38, then by all means give T.38 a try, assuming your Grandstream devices can act as T.38 gateways (it's not enough for them to have T.38 passthrough support, they must have GATEWAY functionality). Once you finally get past all of the interop issues, T.38 really can work magic for FoIP on uncontrolled IP links. If you are using T.38 (or, heck, even if you aren't using T.38), try forcibly lowering the maximum modulation rate that their fax machine will attempt to handshake to the other side with. It is still (sadly) incredibly common for most production T.38 implementations these days to be based off of version 0, which does not include support for gatewaying V.34, only V.17. If they have a Super G3 fax machine, the T.38 gateway feature should in theory just ignore the handshake and not even engage and try to re-INVITE to T.38, but you never know...could be buggy. Or if you aren't using T.38, V.34 modulation rates could be more sensitive to timing and jitter issues. So limit the fax machine to 14400bps or 9600bps. Hope this helps, -- Nathan Anderson First Step Internet, LLC nath...@fsr.com ___ Wireless mailing list Wireless@wispa.org http://lists.wispa.org
Re: [WISPA] OT Fax over Voip
On 4/2/2014 9:03 AM, wi...@mncomm.com wrote: OK, I will. Right now its on my remote techs bench with a Cat5e cable and a switch between the 2 devices. Where this will be going is a farmers elevator site 150 feet between the 2 buildings using UBNT NSM5 radios, excellent quality. Right now they are using 5 VoIP NEC phones at the remote site, plus the same link is carrying their data needs as well, for 5 PCs. I didn’t build separate VLANs as it is a very small network. Regardless I cannot get these to work 10 feet to each other over cable. Voice works great. I will have my tech put together what he has done. He has several hours into it. Usually we wouldn’t dive into stuff too deep, but this customer also hosts a major site for us using their grain leg I'll second Nathan's advice, stressing that you MUST set it to G.711, not any kind of compressed encoding. There's voice, and there's voice-grade. The PSTN is voice-grade, which means it carries voice and other things, like modems, that work across a channel designed for voice but capable of carrying other signals in the 100-3700 Hz range. Cellular and VoIP often compress the voice down using a codec that leaves actual human speech intelligible to a human ear, but doesn't support modems (like the ones in fax). So even if the voice sounds good, it might just be a lower-rate codec recreating voice, not transmitting voice-grade signals. But in addition to that, I STRONGLY recommend a separate VLAN for the voice-grade channels. With priority, or reserved bandwidth. TCP/IP in normal operation manages its flow rate by having packets thrown away; that's why the 1G LAN port on your PC doesn't blast a whole file at 1G into a 2M link. It uses packet loss as a signal. TCP applications retransmit and actual human voice is intelligible with some gaps, but modems, including fax, are very unhappy. AirMAX might also come in handy here, if the fax machine's ATA can set the TOS field, but I haven't tried it myself. -Original Message- From: Nathan Anderson Sent: Tuesday, April 01, 2014 8:52 PM To: 'WISPA General List' Subject: Re: [WISPA] OT Fax over Voip On Monday, March 31, 2014 7:04 AM, wi...@mncomm.com wrote: So, the scenario would be the CO goes into a gateway device to convert to digital, goes over the LAN to the other gateway device. That device hooks up to the fax machine. If someone has done this before can you share the products you may have used? The products we have say they will work this way, but no luck, just voice transmission. I may have a bad device as well. If you are talking about a private point-to-point wireless link shot between two buildings across a parking lot or whatever, with excellent link quality characteristics and low jitter and latency, there is no reason that I can think of why moving the fax machine over wouldn't just work. Perhaps you could share with us the following: 1. Model of the Grandstream gateways in question. 2. How you have the gateways configured (e.g., codec being used and such). 3. What equipment you are using to do the wireless shot. 4. Average throughput, latency, and jitter across that link. 5. Whether the link is for phone use only, or is combined voice and data. 6. ...if combined, whether any kind of QoS is being employed to promote voice transmission ahead of data. ...and, most importantly... 7. What exactly happens when you try to send or receive a fax over the gateway devices. A vague it doesn't work description never helped anybody solve anything. :-) Give us details. How does it fail, exactly? How far along does it get? Is it able to transmit a partial page and then the connection drops? Or can it not even complete the handshake with the other fax machine? If it works for voice, I very much doubt you have a bad device, unless it is a software/firmware issue on the device(s). If the device was physically bad, I suspect the defect would present itself in other ways as well. General things to try out and to look out for: If you are using some fancy, efficient voice codec like G.729, turn that crap off. Limit both gateways to negotiate G.711u with each other only. If they have a T.38 option, make sure it is either enabled on both sides, or disabled on both sides...if there is a mismatch, some SIP stacks behave very badly if/when their re-INVITE to T.38 is rejected by the other peer. If the gateway devices support T.38 and it happens to be enabled, try turning it off. The T.38 spec is so vague as to often be useless, and there can be interop problems even between two identical devices (I swear that sometimes vendors don't test their own products...it's infuriating). And on a private, short-haul link like that, I would sure think that using G.711u PCM for both voice and fax transmission would be sufficient and pose no problems. On the other hand, if latency and jitter are sometimes a problem and the quality
Re: [WISPA] OT Fax over Voip
On Wednesday, April 02, 2014 6:04 AM, wi...@mncomm.com wrote: Regardless I cannot get these to work 10 feet to each other over cable. Voice works great. Again, *what* doesn't work? You haven't described the symptoms of not working to us at all. We can only make assumptions without exact details of the problem. How far does it get? Are you losing pages? Parts of pages? Does it not even begin the transmission? Do you have the speaker enabled on the fax machine and can you hear the attempted handshake with the other side? Do you note any differences in how it sounds going between the VoIP gateways and when it is plugged straight into an FXS provided to you directly from the CO? What error message does the fax machine spit out at you, if it does in fact spit one out? -- Nathan Anderson First Step Internet, LLC nath...@fsr.com ___ Wireless mailing list Wireless@wispa.org http://lists.wispa.org/mailman/listinfo/wireless
Re: [WISPA] OT Fax over Voip
On Wednesday, April 02, 2014 6:55 AM, Fred Goldstein wrote: But in addition to that, I STRONGLY recommend a separate VLAN for the voice-grade channels. With priority, or reserved bandwidth. TCP/IP in normal operation manages its flow rate by having packets thrown away; that's why the 1G LAN port on your PC doesn't blast a whole file at 1G into a 2M link. It uses packet loss as a signal. TCP applications retransmit and actual human voice is intelligible with some gaps, but modems, including fax, are very unhappy. Do note that RTP is implemented over UDP, not TCP, so in VoIP, a dropped audio packet is a lost audio packet, not a delayed or even out-of-order audio packet (although those other two things can happen...they just aren't a result of retransmits, or at least not a retransmit initiated by Layer 4). -- Nathan Anderson First Step Internet, LLC nath...@fsr.com ___ Wireless mailing list Wireless@wispa.org http://lists.wispa.org/mailman/listinfo/wireless
Re: [WISPA] OT Fax over Voip
On 4/2/2014 5:24 PM, Nathan Anderson wrote: On Wednesday, April 02, 2014 6:55 AM, Fred Goldstein wrote: But in addition to that, I STRONGLY recommend a separate VLAN for the voice-grade channels. With priority, or reserved bandwidth. TCP/IP in normal operation manages its flow rate by having packets thrown away; that's why the 1G LAN port on your PC doesn't blast a whole file at 1G into a 2M link. It uses packet loss as a signal. TCP applications retransmit and actual human voice is intelligible with some gaps, but modems, including fax, are very unhappy. Do note that RTP is implemented over UDP, not TCP, so in VoIP, a dropped audio packet is a lost audio packet, not a delayed or even out-of-order audio packet (although those other two things can happen...they just aren't a result of retransmits, or at least not a retransmit initiated by Layer 4). I guess my grammar was a bit rough there! So you're of course right. TCP applications retransmit. (period) Actual human voice (which doesn't retransmit, as it can't wait) is intelligible some gaps. Modes, however, including fax, are very unhappy with gaps. And stressing Nathan's previous note (*what* doesn't work?), this may be one of those *rare* occasions when a video (YouTube anyone?) might actually help. Although the audio alone is more important. If we could (see and) hear the call being dialed by the originating fax, hear what the ring sequence sounded like, and heard the response, with the speaker belching the CNG tone all along, it might help identify the problem. But really, fax and VoIP don't get along very well unless you really tune the VoIP network up to support it. And I know how some faxes are picky. My office fax line sat here virtually unused for years, but my wife needs to receive faxes regularly. Her fax is on a Comcast PacketCable (they call it VoIP but it's really managed VuIP) line that is shared with her office phone and answering machine. My fax (both are Brothers) can send hers a fax. The answering machine gives its spiel, starts to listen, then the fax hears CNG and cuts off the answering machine and sends modem tones. Just like it's supposed to work. But the fancy new fax server system at the courthouse just won't send to it. (Nor will some sizeable fraction of other machines.) It will send to mine, which isn't shared with an answering machine, but not one that is. Picky picky. Fax is like that. -- Fred R. Goldstein k1io fred at interisle.net Interisle Consulting Group +1 617 795 2701 ___ Wireless mailing list Wireless@wispa.org http://lists.wispa.org/mailman/listinfo/wireless
Re: [WISPA] OT Fax over Voip
I havent got my tech to log what he has done so far. Lines will connect to and from remote fax machines, no handshake apparently, no talky over the devices. I will be more descriptive shortly. Sucks that he is four hours away and a rookie compared to me with telephony, not that I am much better haha -Original Message- From: Fred Goldstein Sent: Wednesday, April 02, 2014 5:08 PM To: wireless@wispa.org Subject: Re: [WISPA] OT Fax over Voip On 4/2/2014 5:24 PM, Nathan Anderson wrote: On Wednesday, April 02, 2014 6:55 AM, Fred Goldstein wrote: But in addition to that, I STRONGLY recommend a separate VLAN for the voice-grade channels. With priority, or reserved bandwidth. TCP/IP in normal operation manages its flow rate by having packets thrown away; that's why the 1G LAN port on your PC doesn't blast a whole file at 1G into a 2M link. It uses packet loss as a signal. TCP applications retransmit and actual human voice is intelligible with some gaps, but modems, including fax, are very unhappy. Do note that RTP is implemented over UDP, not TCP, so in VoIP, a dropped audio packet is a lost audio packet, not a delayed or even out-of-order audio packet (although those other two things can happen...they just aren't a result of retransmits, or at least not a retransmit initiated by Layer 4). I guess my grammar was a bit rough there! So you're of course right. TCP applications retransmit. (period) Actual human voice (which doesn't retransmit, as it can't wait) is intelligible some gaps. Modes, however, including fax, are very unhappy with gaps. And stressing Nathan's previous note (*what* doesn't work?), this may be one of those *rare* occasions when a video (YouTube anyone?) might actually help. Although the audio alone is more important. If we could (see and) hear the call being dialed by the originating fax, hear what the ring sequence sounded like, and heard the response, with the speaker belching the CNG tone all along, it might help identify the problem. But really, fax and VoIP don't get along very well unless you really tune the VoIP network up to support it. And I know how some faxes are picky. My office fax line sat here virtually unused for years, but my wife needs to receive faxes regularly. Her fax is on a Comcast PacketCable (they call it VoIP but it's really managed VuIP) line that is shared with her office phone and answering machine. My fax (both are Brothers) can send hers a fax. The answering machine gives its spiel, starts to listen, then the fax hears CNG and cuts off the answering machine and sends modem tones. Just like it's supposed to work. But the fancy new fax server system at the courthouse just won't send to it. (Nor will some sizeable fraction of other machines.) It will send to mine, which isn't shared with an answering machine, but not one that is. Picky picky. Fax is like that. -- Fred R. Goldstein k1io fred at interisle.net Interisle Consulting Group +1 617 795 2701 ___ Wireless mailing list Wireless@wispa.org http://lists.wispa.org/mailman/listinfo/wireless ___ Wireless mailing list Wireless@wispa.org http://lists.wispa.org/mailman/listinfo/wireless
Re: [WISPA] OT Fax over Voip
I've seen pretty good luck with T38 for faxing over VOIP. Obviously, This only works for faxing. Not alarms..etc. Nick Olsen Network Operations (855) FLSPEED x106 From: wi...@mncomm.com Sent: Monday, March 31, 2014 10:04 AM To: WISPA General List wireless@wispa.org Subject: [WISPA] OT Fax over Voip I have a customer that we installed an IP phone system for. They moved their office to a new building where the telco couldn't or wouldn't bring service to. So I have the PBX at their old location where the COs come in and we go over a wireless link to the new office where they use their internet and IP phones, and all works great. So their fax machine sits at their old location and they want it in their new location. They are not interested in doing Internet fax at this time, but I may have to introduce it again. A while ago we bought some Grandstream gateway devices. We have them configured correctly and they transmit and receive voice just fine, just no fax. So, the scenario would be the CO goes into a gateway device to convert to digital, goes over the LAN to the other gateway device. That device hooks up to the fax machine. If someone has done this before can you share the products you may have used? The products we have say they will work this way, but no luck, just voice transmission. I may have a bad device as well. Also, is there any internet fax services that allow users to use their existing fax machine? I know it's a little weird to ask that, but some people have a hard time with change using their PC to send faxes thanks heith mnwireless ___ Wireless mailing list Wireless@wispa.org http://lists.wispa.org/mailman/listinfo/wireless
Re: [WISPA] OT Fax over Voip
Vitality’s Fax Enable product allows ATA with fax machine but they have a monthly minimum. FaxSipit is another company we have used that does Fax ATA services with no minimum. Both work well. Chris From: wireless-boun...@wispa.org [mailto:wireless-boun...@wispa.org] On Behalf Of wi...@mncomm.com Sent: Monday, March 31, 2014 10:04 AM To: WISPA General List Subject: [WISPA] OT Fax over Voip I have a customer that we installed an IP phone system for. They moved their office to a new building where the telco couldn’t or wouldn’t bring service to. So I have the PBX at their old location where the COs come in and we go over a wireless link to the new office where they use their internet and IP phones, and all works great. So their fax machine sits at their old location and they want it in their new location. They are not interested in doing Internet fax at this time, but I may have to introduce it again. A while ago we bought some Grandstream gateway devices. We have them configured correctly and they transmit and receive voice just fine, just no fax. So, the scenario would be the CO goes into a gateway device to convert to digital, goes over the LAN to the other gateway device. That device hooks up to the fax machine. If someone has done this before can you share the products you may have used? The products we have say they will work this way, but no luck, just voice transmission. I may have a bad device as well. Also, is there any internet fax services that allow users to use their existing fax machine? I know it’s a little weird to ask that, but some people have a hard time with change using their PC to send faxes thanks heith mnwireless ___ Wireless mailing list Wireless@wispa.org http://lists.wispa.org/mailman/listinfo/wireless
Re: [WISPA] OT Fax over Voip
On Monday, March 31, 2014 8:51 AM, l...@mwtcorp.net wrote: I don't want to start a long thread about fax but --RANT [...snip excellent fax rant...] +1 -- Nathan Anderson First Step Internet, LLC nath...@fsr.com ___ Wireless mailing list Wireless@wispa.org http://lists.wispa.org/mailman/listinfo/wireless
Re: [WISPA] OT Fax over Voip
On Monday, March 31, 2014 7:04 AM, wi...@mncomm.com wrote: So, the scenario would be the CO goes into a gateway device to convert to digital, goes over the LAN to the other gateway device. That device hooks up to the fax machine. If someone has done this before can you share the products you may have used? The products we have say they will work this way, but no luck, just voice transmission. I may have a bad device as well. If you are talking about a private point-to-point wireless link shot between two buildings across a parking lot or whatever, with excellent link quality characteristics and low jitter and latency, there is no reason that I can think of why moving the fax machine over wouldn't just work. Perhaps you could share with us the following: 1. Model of the Grandstream gateways in question. 2. How you have the gateways configured (e.g., codec being used and such). 3. What equipment you are using to do the wireless shot. 4. Average throughput, latency, and jitter across that link. 5. Whether the link is for phone use only, or is combined voice and data. 6. ...if combined, whether any kind of QoS is being employed to promote voice transmission ahead of data. ...and, most importantly... 7. What exactly happens when you try to send or receive a fax over the gateway devices. A vague it doesn't work description never helped anybody solve anything. :-) Give us details. How does it fail, exactly? How far along does it get? Is it able to transmit a partial page and then the connection drops? Or can it not even complete the handshake with the other fax machine? If it works for voice, I very much doubt you have a bad device, unless it is a software/firmware issue on the device(s). If the device was physically bad, I suspect the defect would present itself in other ways as well. General things to try out and to look out for: If you are using some fancy, efficient voice codec like G.729, turn that crap off. Limit both gateways to negotiate G.711u with each other only. If they have a T.38 option, make sure it is either enabled on both sides, or disabled on both sides...if there is a mismatch, some SIP stacks behave very badly if/when their re-INVITE to T.38 is rejected by the other peer. If the gateway devices support T.38 and it happens to be enabled, try turning it off. The T.38 spec is so vague as to often be useless, and there can be interop problems even between two identical devices (I swear that sometimes vendors don't test their own products...it's infuriating). And on a private, short-haul link like that, I would sure think that using G.711u PCM for both voice and fax transmission would be sufficient and pose no problems. On the other hand, if latency and jitter are sometimes a problem and the quality of the link is in doubt, and you haven't been using T.38, then by all means give T.38 a try, assuming your Grandstream devices can act as T.38 gateways (it's not enough for them to have T.38 passthrough support, they must have GATEWAY functionality). Once you finally get past all of the interop issues, T.38 really can work magic for FoIP on uncontrolled IP links. If you are using T.38 (or, heck, even if you aren't using T.38), try forcibly lowering the maximum modulation rate that their fax machine will attempt to handshake to the other side with. It is still (sadly) incredibly common for most production T.38 implementations these days to be based off of version 0, which does not include support for gatewaying V.34, only V.17. If they have a Super G3 fax machine, the T.38 gateway feature should in theory just ignore the handshake and not even engage and try to re-INVITE to T.38, but you never know...could be buggy. Or if you aren't using T.38, V.34 modulation rates could be more sensitive to timing and jitter issues. So limit the fax machine to 14400bps or 9600bps. Hope this helps, -- Nathan Anderson First Step Internet, LLC nath...@fsr.com ___ Wireless mailing list Wireless@wispa.org http://lists.wispa.org/mailman/listinfo/wireless
[WISPA] OT Fax over Voip
I have a customer that we installed an IP phone system for. They moved their office to a new building where the telco couldn’t or wouldn’t bring service to. So I have the PBX at their old location where the COs come in and we go over a wireless link to the new office where they use their internet and IP phones, and all works great. So their fax machine sits at their old location and they want it in their new location. They are not interested in doing Internet fax at this time, but I may have to introduce it again. A while ago we bought some Grandstream gateway devices. We have them configured correctly and they transmit and receive voice just fine, just no fax. So, the scenario would be the CO goes into a gateway device to convert to digital, goes over the LAN to the other gateway device. That device hooks up to the fax machine. If someone has done this before can you share the products you may have used? The products we have say they will work this way, but no luck, just voice transmission. I may have a bad device as well. Also, is there any internet fax services that allow users to use their existing fax machine? I know it’s a little weird to ask that, but some people have a hard time with change using their PC to send faxes thanks heith mnwireless ___ Wireless mailing list Wireless@wispa.org http://lists.wispa.org/mailman/listinfo/wireless
Re: [WISPA] OT Fax over Voip
There's a company that has boxes that'll work even over a satellite connection. I forget their name. Google for satellite fax. - Mike Hammett Intelligent Computing Solutions http://www.ics-il.com - Original Message - From: wi...@mncomm.com To: WISPA General List wireless@wispa.org Sent: Monday, March 31, 2014 9:03:51 AM Subject: [WISPA] OT Fax over Voip I have a customer that we installed an IP phone system for. They moved their office to a new building where the telco couldn’t or wouldn’t bring service to. So I have the PBX at their old location where the COs come in and we go over a wireless link to the new office where they use their internet and IP phones, and all works great. So their fax machine sits at their old location and they want it in their new location. They are not interested in doing Internet fax at this time, but I may have to introduce it again. A while ago we bought some Grandstream gateway devices. We have them configured correctly and they transmit and receive voice just fine, just no fax. So, the scenario would be the CO goes into a gateway device to convert to digital, goes over the LAN to the other gateway device. That device hooks up to the fax machine. If someone has done this before can you share the products you may have used? The products we have say they will work this way, but no luck, just voice transmission. I may have a bad device as well. Also, is there any internet fax services that allow users to use their existing fax machine? I know it’s a little weird to ask that, but some people have a hard time with change using their PC to send faxes thanks heith mnwireless ___ Wireless mailing list Wireless@wispa.org http://lists.wispa.org/mailman/listinfo/wireless ___ Wireless mailing list Wireless@wispa.org http://lists.wispa.org/mailman/listinfo/wireless
Re: [WISPA] OT Fax over Voip
http://www.vitelity.com/services_vfax/ Works perfect. Order the Fax Enable device and it will allow the old fax machine to function perfectly. You also get the benefit of fax-to-email capability if they want it turned on. Unless they do a ton of faxes each month, the standard per minute rates are the way to go. On Mon, Mar 31, 2014 at 9:03 AM, wi...@mncomm.com wrote: I have a customer that we installed an IP phone system for. They moved their office to a new building where the telco couldn't or wouldn't bring service to. So I have the PBX at their old location where the COs come in and we go over a wireless link to the new office where they use their internet and IP phones, and all works great. So their fax machine sits at their old location and they want it in their new location. They are not interested in doing Internet fax at this time, but I may have to introduce it again. A while ago we bought some Grandstream gateway devices. We have them configured correctly and they transmit and receive voice just fine, just no fax. So, the scenario would be the CO goes into a gateway device to convert to digital, goes over the LAN to the other gateway device. That device hooks up to the fax machine. If someone has done this before can you share the products you may have used? The products we have say they will work this way, but no luck, just voice transmission. I may have a bad device as well. Also, is there any internet fax services that allow users to use their existing fax machine? I know it's a little weird to ask that, but some people have a hard time with change using their PC to send faxes thanks heith mnwireless ___ Wireless mailing list Wireless@wispa.org http://lists.wispa.org/mailman/listinfo/wireless -- Darin Steffl Minnesota WiFi www.mnwifi.com 507-634-WiFi http://www.facebook.com/minnesotawifi Like us on Facebookhttp://www.facebook.com/minnesotawifi ___ Wireless mailing list Wireless@wispa.org http://lists.wispa.org/mailman/listinfo/wireless
Re: [WISPA] OT Fax over Voip
On 3/31/2014 10:03 AM, wi...@mncomm.com wrote: I have a customer that we installed an IP phone system for. They moved their office to a new building where the telco couldn't or wouldn't bring service to. So I have the PBX at their old location where the COs come in and we go over a wireless link to the new office where they use their internet and IP phones, and all works great. So their fax machine sits at their old location and they want it in their new location. They are not interested in doing Internet fax at this time, but I may have to introduce it again. A while ago we bought some Grandstream gateway devices. We have them configured correctly and they transmit and receive voice just fine, just no fax. So, the scenario would be the CO goes into a gateway device to convert to digital, goes over the LAN to the other gateway device. That device hooks up to the fax machine. If someone has done this before can you share the products you may have used? The products we have say they will work this way, but no luck, just voice transmission. I may have a bad device as well. Also, is there any internet fax services that allow users to use their existing fax machine? I know it's a little weird to ask that, but some people have a hard time with change using their PC to send faxes Which solution is best for the customer depends on how they use fax and how critical it is. I just uploaded my FCC Comments on the ATT experiment, one which proposes that fax capabilities be lost. I pointed out that fax is sometimes used for reasons that distinguish it from email: Security and privacy (no middle man server), knowledge of receipt (not just to a mailbox), and reliability (no servers, no attachments). Internet fax is actually the worst of both worlds, putting fax in series with email. So it's useful if you get the occasional fax from someone who can't scan documents otherwise, but it's not useful if you use fax the way pharmacies, doctors, and courts do. Since VoIP doesn't support modems or fax, if they need real fax, they need a way to extend the signal (dial tone) to the new site. This can't just run over best efforts IP. But there are systems that do the timing and buffering to enable TDM to be reliably emulated across a wireless link (I suggest using a high-priority VLAN and no public IP). We're using the RAD IPmux series. We're putting them in to replace T1s, for instance, to support fire department voting receivers (very quality critical) across Ethernet radios. Not exactly cheap, but it's a nice tool. They are available with different types of interfaces. -- Fred R. Goldstein k1io fred at interisle.net Interisle Consulting Group +1 617 795 2701 ___ Wireless mailing list Wireless@wispa.org http://lists.wispa.org/mailman/listinfo/wireless
Re: [WISPA] OT Fax over Voip
On Mon, 31 Mar 2014 11:09:31 -0400 Fred Goldstein fgoldst...@ionary.com wrote: On 3/31/2014 10:03 AM, wi...@mncomm.com wrote: I have a customer that we installed an IP phone system for. They moved their office to a new building where the telco couldn't or wouldn't bring service to. --snip-- Which solution is best for the customer depends on how they use fax and how critical it is. I just uploaded my FCC Comments on the ATT experiment, one which proposes that fax capabilities be lost. I pointed out that fax is sometimes used for reasons that distinguish it from email: Security and privacy (no middle man server), knowledge of receipt (not just to a mailbox), and reliability (no servers, no attachments). I don't want to start a long thread about fax but --RANT Fax over copper was never either secure or private. The transmission always was fairly easy to intercept if you were snooping on a particular individual/business. Plus, you have no idea who walks up to the recipient fax machine which I maintain should disqualify it for both the legal and medical communities. Some of the old time phone phreaks used to have the CO automatically bridge lines to a cable pair that they had acquired during call setup. (Hopefully they were all chased out of the system some time ago) Fax is a loose standard and should have died out a decade ago. (IMHO) A peer-to-peer encrypted, standards based system would have been the likely result and this silliness about supporting analog fax would go away. /RANT That said both of the methods mentioned in this thread work about as well as traditional copper which is less than 100%. Even on copper expect a few customer calls. Internet fax is actually the worst of both worlds, putting fax in series with email. So it's useful if you get the occasional fax from someone who can't scan documents otherwise, but it's not useful if you use fax the way pharmacies, doctors, and courts do. Since VoIP doesn't support modems or fax, if they need real fax, they need a way to extend the signal (dial tone) to the new site. This can't just run over best efforts IP. But there are systems that do the timing and buffering to enable TDM to be reliably emulated across a wireless link (I suggest using a high-priority VLAN and no public IP). We're using the RAD IPmux series. We're putting them in to replace T1s, for instance, to support fire department voting receivers (very quality critical) across Ethernet radios. Not exactly cheap, but it's a nice tool. They are available with different types of interfaces. -- Fred R. Goldstein k1io fred at interisle.net Interisle Consulting Group +1 617 795 2701 Larry Ash Network Administrator Mountain West Telephone 123 W 1st St. Casper, WY 82601 Office 307 233-8387 ___ Wireless mailing list Wireless@wispa.org http://lists.wispa.org/mailman/listinfo/wireless