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Sending fax problem

Started by Thomike, June 09, 2019, 12:46:55 PM

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Thomike

My new OBI200 with Google Voice seems perfect for phone calls.
But there is a problem to send fax (from USA to USA).
The Printer/Copier/Fax is a Brother MFC-J4620DW with Basic compatibility setting (means "For VOIP" i.e. reduces the modem speed to 9,600 bps).
Unfortunately the distant fax takes the line and hang up after about 2 seconds.
Any idea? 

SteveInWA

There are many years of discussions about faxing via VoIP.  The bottom line is that it is unreliable at best, and it can be frustrating to get it to work at all.  There is no silver bullet, despite various posts about various arcane settings changes.

Given that you're already limiting it to the recommended maximum speed, the other setting that makes a big difference is to turn OFF the fax machine's error correction.  EC on fax is very primitive; all it does is tell the sending machine to resend the page.  It's unforgiving.  If it can't successfully send the page, it will just give up and hang up.  With EC off, you will probably get some messes on some pages (stripes, garbled characters, etc), but at least it should send.

Bottom line:  simply avoid sending faxes that way.  Instead, use a email-to-fax gateway, or a service that allows you to upload a PDF or JPG file to send.  Their fax servers will handle the actual fax communication.  You can also receive faxes that way, far more reliably.  Of course, you can also scan and email the document as an attachment, or use a file sharing service like Google Drive, Microsoft Onedrive, or Dropbox.

Thomike

Thank you very much Steve.
Unfortunately, all the communication, advertising and even the box of my new OBI200 says (too) clearly "Port VoIP Phone Adapter with Google Voice and Fax Support". That seems to me to be a lie....
I am perfectly aware of the other possibilities of sending files besides faxes, but I would have appreciated a reliable fax system for communications with doctors, laboratories, pharmacists or hospitals who refuse any sending by email.
In the absence of a satisfactory solution, I would probably have to return my OBI200 to Amazon and express my dissatisfaction very widely.
   

drgeoff

#3
Quote from: Thomike on June 09, 2019, 01:36:40 PM
Thank you very much Steve.
Unfortunately, all the communication, advertising and even the box of my new OBI200 says (too) clearly "Port VoIP Phone Adapter with Google Voice and Fax Support". That seems to me to be a lie....
I am perfectly aware of the other possibilities of sending files besides faxes, but I would have appreciated a reliable fax system for communications with doctors, laboratories, pharmacists or hospitals who refuse any sending by email.
In the absence of a satisfactory solution, I would probably have to return my OBI200 to Amazon and express my dissatisfaction very widely.
 
The "Fax Support" means that the OBi ATA implements ITU-T Recommendation T.38. (https://www.itu.int/rec/T-REC-T.38-201511-I/en).  However that can only come into play if there is another T.38 equipped entity at the other end of the IP part of the transmission path to/from the other fax terminal. In your case that is where Google Voice connects to the POTS network.  I am  not aware that GV has T.38 support.

Taoman

Quote from: Thomike on June 09, 2019, 01:36:40 PM
Thank you very much Steve.
Unfortunately, all the communication, advertising and even the box of my new OBI200 says (too) clearly "Port VoIP Phone Adapter with Google Voice and Fax Support". That seems to me to be a lie....
 

How so? The OBi200 supports the T.38 fax standard. That's 100% true.
Steve referred to "faxing via VoIP" as being inherently unreliable. That is also true.
Lots of people fax successfully using OBi ATAs. I just wouldn't bet the farm on it working every time you try it.

azrobert

#5
You can try this:
http://www.obitalk.com/forum/index.php?topic=6625.msg41922#msg41922

Edit:
This is a very old post and I don't know if it still applies.

SteveInWA

Quote from: azrobert on June 09, 2019, 04:22:20 PM
You can try this:
http://www.obitalk.com/forum/index.php?topic=6625.msg41922#msg41922

Edit:
This is a very old post and I don't know if it still applies.

I specifically did not suggest any such fiddling, because it doesn't work.  Don't rely on a six-year-old post, especially if you read through to the bottom of that discussion and saw that it doesn't work as of that date of that last post.

In general, these failures occur when the ISP connection, or one or more of the carriers in the path, are unstable.  The fax protocol was designed for old-fashioned POTS lines, not for VoiP.  That's why the T.38 standard was developed, but it was largely a flop, due to lack of implementation by fax machines or terminals.

Thomike

Thank you to everyone for their technical contribution.

I understand that this IP faxing technique is not yet fully developed and I do not appreciate Polycom Obihai's commercial communication at all, which has suggested that it is operational.

I suspected my 4-year-old Brother multifunction printer and I was considering using a recent USB 56K External Dial Up Voice Fax Data Modem Windows 10 connected to the OBi200, but what I read is not in favor of this formula.

In Europe, a few years ago, I used a lot of Internet boxes providing 2 telephone lines without any problem. It was telephony and fax over IP. I am very surprised that the Polycom OBi200 system does not allow the same service for communication by fax.

SteveInWA

This has absolutely, positively nothing whatsoever to do with the OBiTALK device's capabilities or quality.

It is caused by a less-than-perfect Internet service provider connection, or by other telephone-network factors, that are causing dropped packets or related issues.  It doesn't matter which ATA you are using.  It either works or it doesn't.

Digital telephone service provided by cable or fiber uses a private, managed network, vs. the public Internet.  It is a "cleaner" and more direct connection into the telephone network, and it works great for faxing and security alarms.  You can't duplicate that level of quality via the public Internet, unless you have a high-quality connection.

I have FiOS (fiber optic) Internet service.  I can reliably send faxes, using my HP OfficeJet multi-function machine, over Google Voice.  I can't reliably send faxes over some other VoIP service providers.

Don't blame Polycom for this.  It's not their fault. You'd have the same problem using some other brand of ATA.

azrobert

Quote from: SteveInWA on June 09, 2019, 05:56:03 PM
I specifically did not suggest any such fiddling, because it doesn't work.  Don't rely on a six-year-old post, especially if you read through to the bottom of that discussion and saw that it doesn't work as of that date of that last post.

Just because it didn't work for that user doesn't mean it won't work. Here is a 2 1/2 year old post where it did work. It will only take a few minutes to configure, so why not try.

http://www.obitalk.com/forum/index.php?topic=12259.msg78259#msg78259


drgeoff

Quote from: SteveInWA on June 09, 2019, 05:56:03 PM.... the T.38 standard was developed, but it was largely a flop, due to lack of implementation by fax machines or terminals.
Fax machines and terminals which connect to analogue "lines" (POTS lines, analogue side of ATAs etc) do not implement T.38.  That is the whole point.  The purpose of T.38 is to "hide" the vagaries of IP and VoIP so that the end to end connection appears to the fax machines to be and to have the properties of a POTS path.  No change to existing fax machines was required.

T.38 needs to be implemented at the junctions POTS* to VoIP and VoIP to POTS*.  An ATA is one such location and OBi200/202/212/300/302 devices do have it.  However it cannot function if T.38 is not present at the other point where POTS* and VoIP interchange. That is commonly where an ITSP connects its VoIP customers to POTS*.

(* These POTS are not necessarily analogue.  More often they will be PCM, G.711.)

Thomike

For Steve: here is my Internet speed. What else is needed?

If there are any, I would have greatly appreciated clear, perfectly operational instructions printed in the Polycom OBi200 Installation & Configuration Guide.

I also read that the OBi202 could fax on only one of its two lines. I can still change for this model if I was sure it would work.

For the time being, I would like to thank everyone for the suggestions provided. This will take time and multiple tests for a very uncertain result.

It is this situation that I strongly reproach Polycom Obihai for providing very interesting hardware but with fanciful promises to say the least.

drgeoff

#12
@Thomike

Your internet speed is not the issue. Fax machines use modems to communicate over POTS and those modem standards were devised (many years ago before VoIP) to accommodate the types of distortion and impairment that POTS suffers from. A VoIP circuit has completely different types of distortion and impairment. Some arise from the nature of IP - lost packets, packet jitter, seriously delayed packets, out of order packets. Others arise from codecs which are heavily optimised for speech, not modem tones. Consequently, fax transmission between analogue fax machines over VoIP has uncertain success.

T.38 was developed to address that but as I explained above it can only work if implemented at the necessay points in the end to end path. There is no compulsion for network operators and service providers to implement T.38. Outside of Japan, fax is small beer.

Having said all that, I do have a Brother MFC-J4510DW connected to my OBi110 (which does not have T.38) which I occasionally use to send faxes to Japan using Localphone (UK) as ITSP. Most times, but not always, transmission is successful.

The two phone ports of an OBi202 behave identically. It may be that the processor does not have enough grunt to run the T.38 processing on two fax calls taking place simultaneously. That is speculation on my part but I cannot think of any other reason for what you claim to have read. When T.38 is not in use an OBi treats a fax call in the same way as a voice call and an OBi202 is certainly capable of two simultaneous voice calls. You will not have an improved result by changing from an OBi200 to any other OBi model.

Regarding "GV and fax support", that to me does not mean that faxes are claimed to work if GV is the ITSP.

Sheffield_Steve

I have a Obi200 and use Callcentric.  My Canon MF247dw multi-function machine send faxes perfectly every time and has no changes to the default settings.  I've never tried it with GVoice though


drgeoff

#14
Quote from: Sheffield_Steve on June 10, 2019, 08:04:39 AM
I have a Obi200 and use Callcentric.  My Canon MF247dw multi-function machine send faxes perfectly every time and has no changes to the default settings.  I've never tried it with GVoice though
I was about to suggest that Thomike investigate other service providers who do support T.38.  Callcentric is one of them - https://www.callcentric.com/faq/30#205 is worth reading.

Sheffield_Steve

I just tried faxing with my Canon and GVoice - no luck after multiple tries.  It fails when negotiating a connection.  I did not try modifying any settings.

Thomike

Thanks a lot to Sheffield_Steve and drgeoff.

Finally, I can send and receive faxes with Callcentric.
Unfortunately, that seems difficult or probably impossible with GV.

Note that for voice, Google Voice (GV) works correctly.
So I have 2 active phone numbers (Callcentric & GV), on my OBi200 which is connected in parallel to a telephone handset as well as to my fax (multifunction printer). The calls from each line come well on the Obi200 which makes both ring. The fax machine takes the call if I don't pick up the phone.
For outgoing calls, faxes and even 911 (option I activated at Callcentric), I simply dial the number requested and it goes through Callcentric.
If I want to make an outgoing phone call via GV, I have to dial **2 and then of course the number requested.

Such information would have been very much appreciated in the Polycom OBi200 Installation & Configuration Guide.
That would have saved a lot of time.