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#94282 by snow_loon
Thu Mar 22, 2012 6:54 pm
I have been having good LUCK with faxing (with *98- prefix) until today. So, I'd sure like to see an Ooma Faxing 101 Support Forum. Faxing posts are spread out over several sub-forums.

I've seen the star codes (https://www.ooma.com/app/support/star-co ... oma-device) but have a number of questions:
1) can you use multiple codes such as *98-*99- to improve chances of a fax being successful?
2) Will *70 "Disable Call-Waiting Tone" improve fax performance? Is it possible to turn this off permanently or reduce volume? As I understand *70, it will prevent the disruptive beeps announcing a second incoming call. My wife is hard-of-hearing and can't understand the first caller. Is it possible my fax machine is hard-of-hearing as well?
3) Several faxes were successful without turning off error mode in the fax machine. Why is this recommended? It seems counter intuitive to a newb. If I'm getting errors, why turn off the function which should resolve errors?
4) Is a space (blank) the same as a pause (-) in the fax phone number? What are the rules for use of such pauses? If *70 and *98 are compatible, would it be *98*70- *70-*98- or some other prefix combination?

Any clarification of the star codes would be much appreciated. Thanks.
#94293 by EX Bell
Fri Mar 23, 2012 8:30 am
snow_loon wrote:I have been having good LUCK with faxing (with *98- prefix) until today. So, I'd sure like to see an Ooma Faxing 101 Support Forum. Faxing posts are spread out over several sub-forums.

I've seen the star codes (https://www.ooma.com/app/support/star-co ... oma-device) but have a number of questions:
1) can you use multiple codes such as *98-*99- to improve chances of a fax being successful?
2) Will *70 "Disable Call-Waiting Tone" improve fax performance? Is it possible to turn this off permanently or reduce volume? As I understand *70, it will prevent the disruptive beeps announcing a second incoming call. My wife is hard-of-hearing and can't understand the first caller. Is it possible my fax machine is hard-of-hearing as well?
3) Several faxes were successful without turning off error mode in the fax machine. Why is this recommended? It seems counter intuitive to a newb. If I'm getting errors, why turn off the function which should resolve errors?
4) Is a space (blank) the same as a pause (-) in the fax phone number? What are the rules for use of such pauses? If *70 and *98 are compatible, would it be *98*70- *70-*98- or some other prefix combination?

Any clarification of the star codes would be much appreciated. Thanks.


1) Not to my knowledge. Single prefix at a time, but need an old salt to confirm.
2) Doubt it. *98 is going to use the G.711 codec which supports fax over IP networks. If you're lucky like me, your machine doesn't technically support it, but it works. If you have a fax machine that supports it, you should have more reliable results. *99 might work for some fax machines, but didn't for mine. If it was working before, but isn't working now, it could be your internet connection. You can check your connection with Phone Power and then post your stats below. Someone will likely respond with recommendations of what they should be and how to correct it.
3) Error correction is for traditional POTS which is has very little loss. Turning on error correction on a VoIP connection which has a quite a bit of loss as a norm, causes havoc with the communication. More info from [urlhttp://www.voipmechanic.com/faxingissuesandotherdevices.htm]VoIP mechanic[/url].
4) No idea. My multifunciton/fax machine (Samsung SCX-4521F) allows entry of the dialing prefix into the fax settings, so you don't need to dial it each time. Like would be used with a PBX where you need to dial 9 first, to get an outside line.

After running the test at Phone Power, click the last tab and post the results of the following:

Download Speed:
Upload Speed:
Download consistency of Service:
Upload consistency of Service:
Maximum TCP delay:
Average download pause:
Minimum round trip time to server:
Average round trip time to server:
Estimated download bandwidth:
Route concurrency:
Download TCP forced idle:
Maximum route speed:
Jitter: you --> server:
Jitter: server--> you:
Packet loss: you--> server:
Packet loss: server--> you:
Packet discards:
Packets out of order:
Estimated MOS score:
#94295 by snow_loon
Fri Mar 23, 2012 9:03 am
Here's a follow-up on my status. I started with a 19 page package to fax. For the second attempt, I tried using the prefix
*98-*70-3334444 - two star codes, each followed by a pause, followed by a 7-digit local phone number. The - represents a pause on my fax (HP OfficeJet 5610 AIO printer).
I made no other changes such as reducing the speed or turning off the CCITT/ITU Group 3 error correction mode.
Then tried the full 19 page package which failed on about page 7.
I ended up sending 6 faxes with a maximum of 5 pages per fax, using the two star codes. Most of these were succusseful (at least from my perspective).
The company receiving this didn't seem real happy, but promised to let me know early next week if they needed the whole package re-faxed...
Are there any recommendations from those successful with faxing, or from an Ooma Guru?
BTW, the Telo voice quality has been very good without router Quality Of Service (QoS). I'll need to invest in a new router for that. Does faxing use a high bandwidth?
My Telo is behind my Netgear WGR614 v9 router. PhonePower gave these results:
Speed test statistics
---------------------
Download speed: 13801 kbps
Upload speed: 4141 kbps
Download consistency of service: 44 %
Upload consistency of service: 98 %
Download test type: socket
Upload test type: socket
Maximum TCP delay: 82 ms
Average download pause: 1 ms
Minimum round trip time to server: 91 ms
Average round trip time to server: 91 ms
Estimated download bandwidth: 13801 kbps
Route concurrency: 1.0
Download TCP forced idle: 49 %
Maximum route speed: --

VoIP test statistics
--------------------
Jitter: you --> server: 0.3 ms
Jitter: server --> you: 0.7 ms
Packet loss: you --> server: 0.0 %
Packet loss: server --> you: 0.0 %
Packet discards: 0.0 %
Packets out of order: 0.0 %
Estimated MOS score: 4.2
#94309 by remaker
Fri Mar 23, 2012 4:08 pm
Faxing is VERY sensitive to jitter (changes in delay) and lost packets. The audio impairments caused by those problems are nothing that the FAX standards have ever been designed to deal with.

http://speedtest.phonepower.com will show your loss and jitter. You need small jitter (6ms or less) and 0% packet loss for any hope of FAX over VoIP.

These parameters can change minute by minute depending on the traffic in your ISP. Even if they just added a new heavy downloader to your segment, that could impact FAX, even though voice would seem unchanged. Ooma's magic is in all of the error correction and masking to make voice work well in an IP environment. FAX is much fussier than the human ear.

You can take it up with your ISP, but unless you have a business class service, most ISPs won't care or help much with packet loss or jitter.

The good news is that a lot of companies are waking up to the end of fax and allowing scanned PDFs to be securely uploaded to a web site. The best way to work with FAX in a VoIP environment is to get rid of it altogether! :-)
#94428 by snow_loon
Wed Mar 28, 2012 2:03 pm
Here's a 2nd update on my faxing issues.
I tried to have my broker send one page via fax. It failed almost immediately. Because the document has highly confidential information, the only option is to have them mail the form cross country.
I have come to the conclusion that fax is an outdated technique. It is much better to scan documents to a PDF and email them, assuming they don't have confidential info like SS#, birthdate, etc.
But, it would sure be nice to have the ability to have a few pages faxed (either sent or received), even a a very reduced speed.

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