VOIP etc > Voice Over IP - VOIP > Vonage > Faxing

Faxing

Here's a thread I found on here »can't get fax to work on vonage It is a little old. Maybe still relevant.
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a little update I tried a 2nd time yesterday and it sent 3 pages ok so it does work but hit or miss.

reply to Subaru
I have faxed many things on my vonage number without any problems I use *99 when I fax.

what does *99 do?

reply to Subaru
Been faxing over Vonage just fine for 8 years...

After 7 years of faxing successfully with Vonage, I cannot send or receive at all. Well, I can to HP's Fax Test Service, 1-888-hpfaxme (1-888-473-2963). Those test faxes go through without a hitch but that is about it. I have done all the steps posted here, on the Vonage forum and on other Websites. Any suggestions?

i hp fax/scanner/printer can successfully fax to any number without fail. but i had to lower the modem speed to 14kbps.

reply to Subaru
Contrary to popular belief, do not disable ECM mode. If you have a super G3 fax, you may set the baud rate to 14400, eg. reverting to regular G3 mode. There is no need to reduce the baud rate to 9600 and lower.

Some might see a higher success rate without ECM. This is because without any sort of error detection, pages may be coming through missing, blank, or cut in the middle. You're essentially telling the fax machine "I don't care if my pages may be unreadable" - so it doesn't perform any error detection whatsoever. ECM mode hence is failing and letting you know that the page(s) wouldn't go though.

I have done extensive testing using fax/modem over VoIP. Many VoIP providers are using the same termination CLECs for their outgoing calls. Their shouldn't be a difference whether you use Vonage vs. some other VoIP provider.

I was in the same situation some years ago and I thought it was great until some important faxes kept coming out with missing pages. After extensive testing, I can find no reason why 9600+no ecm would be more reliable. It is NOT more reliable, only a trick because people that just don't know see the word "success", and they think nothing of it after that. If you're getting failures with ECM mode, then disabling it is certainly giving the receiver missing pages. "Just because it works for you that way"... is simply not true. Even mentioning it will cause others to race into their fax machine and change it. It is simply bad advise.

**A big consideration why 14400 and ECM mode was developed is because of noisy phone lines causing problems over the years. 14400 data rate has Forward error correction; that's in addition to software level ECM - so you get two forms of error detection and correction. whereas 9600 data rate is 1980 technology line based for thermal roll printers with no page buffering ability whatsoever. The line based mode only has error concealment (not correction; that's two different things) Concealment means to approximate the lost data with the previous and next data to try and hide the error to be less visible as possible. Concealment works up to a certain point; sometimes the whole line can be dropped. At worst too big of a data gap will happen and that produces the characteristic page being cut off. And of course you will still get a "success" because there is no error reporting from the receiving machine whatsoever. On VoIP, the data gaps happen due to random high network jitter and packet loss. ECM breaks the pages down into data sets called frames and octets. ECM mode handles this quite well by asking the sending machine for the lost octets. ECM actually tries very hard to deliver a fax; On a marginal VoIP line, it will just take longer than usual as the ECM mode re-transmits lost octets. At worst it will eventually time out or your call will be dropped and give a transmission error, and telling you exactly what pages were not yet delivered. In terms of modem baud rate goes 9600 vs 14400 isn't a big enough difference so that 9600 by raw baud rate alone wouldn't improve reliability very much, but any reliability you gain due to lower baud rate alone is then lost due to the fact you're giving up forward error correction in the modem protocol.

If you were talking about an enterprise grade VoIP solution, I would agree with your recommendations for fax configuration. I install and maintain a number of such enterprise grade VoIP solutions, and they do not have the problems with fax transmission that frequently plague Vonage customers.

There are many reasons for this, but here are a few of the most common ones:

1. Unlike a typical enterprise grade VoIP solution, Vonage does not supply or control the underlying broadband connection itself, and that can (and does) make a major difference in whether or not faxing is even possible for many Vonage customers. Basic problems associated with the quality of that service aside, believe it or not, some ISPs who also offer VoIP services, do delay and/or drop Vonage (or any competitor's) VoIP packets.

2. Not all of the ATAs that Vonage has used even support the T38 protocol for fax transmission.

3. Even for the Vonage ATAs that do support T38, the Vonage firmware in some of those devices has been known to be a defective implementation. Also the Vonage network itself does not fully support the T38 protocol in both directions because not all of the CLECs that Vonage uses support the T38 protocol.

If your Vonage connection can fully support high quality fax transmission in both directions, then bully for you. BTW, do you actually use the Vonage service? Even if you do use Vonage, do not mistake your good fortune as some proof that every Vonage customer has the same good fortune.
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reply to Subaru
Some things are too simple for explanation. On the
old thread that's mentioned earlier, Mediocrates said:

"Make sure your HP fax machine is plugged into the TA using ONLY a 2-wire RJ-11 plug and wire. If you use a 4-wire line it won't work. At least my HP640 won't."

Thank you for a SIMPLE and great solution to my problem...and
maybe to problems that many others are having. Vonage support NEVER made or mentioned a solution to my problem,
and changing to a 2-wire plug and wire fixed it IMMEDIATELY.
A quote from Vonage Support .. "Vonage will not work with
anything but an old fashioned stand-alone fax machine."

Thanks, Mediocrates !

reply to Subaru
Well i tried faxing on viatalk and axvoice but the problem persists and i don't recommend you to use any internet phone service for faxing. Go for the conventional means instead.

reply to Subaru
FYI PSTN will be dead soon so voip is going to be the new phone systems.

I use to have great luck faxing w/ my Vonage line but no longer. If you are an infrequent fax user like myself, there are many free websites that allow you to use their service to fax a couple times daily.