Not able to Fax over VOIP

[sidhupal]

I am a freephone subscriber and have a single phone to my house.
I am using Cisco SPA122 ATA adapter.
When sending fax, the line disconnects/fax transmission does not go through. Tried several numbers, same issue.
On my fax machine, I have tried to reduce the baud rate and disable ECM but no help.

Any idea or other configuration I need to change under Line 1 or 2 to make faxing work?

[Jake]

Faxing via VOIP doesn't really work. Try very simple typed or hand written faxes - this has helped me in the past. What might seem counter-intuitive is to actually increase the quality to very high. I think the reason behind this is because it slows everything down and gives it more time to send. I have a PAP2T which has a T38 option (codec?) on it. Maybe your ATA does also, so just make sure it is enabled.

My best advise is to find an email to fax service, or take it down your local UPS store and send it from there.

[lustucru]

I'm using the faxing capability successfully during the last 10 months but some restrictions apply.

The color documents transmission has always failed.

To make it work, I choose a black & white document scanned in Home mode, resolution 600 or 1200. Also, select the T.38 (Auto detect) faxing mode in your ATA settings.

[faz68]

I have been able to successfully send faxes using my Cisco PAP2T using the following settings:

Before changing any of these settings make note or your original ones.

1. On Line 1 - set network jitter buffer to very high;
2. Disable Change Jitter Buffer Adjustment;
3. Call waiting should be set to NO
4. 3-way calling should be set to NO
5. echo cancellor should be set to NO
6. silence suppression should be set to NO
7. preferred codec should be set to G711a

Change all these setting back to what they were after your done faxing. Also, a cool feature with Fongo is when someone sends
you a fax it should come through via your email (as a PDF) if you have voicemail set up to send you an email
notification with VM attachment.

Good luck!

[jking2175]

I've had great success with faxing over voip.

using the g711a codec is important. Also change your fax machine speed to 9600 baud. Also If you have error correction on your fax try turing it off if you still have problems.

Most newer fax machines use 1400 baud or higher... this is very iffy over voip but at 9600 baud I've had no issues to date.

As with anything on voip jitter, packet loss etc will make faxing brutal.

Try running a test on http://www.pingtest.net/ to verify your internet connection jitter levels etc.

I've never tried the settings faz68 has posted but they also seem logical. 9600 baud though is the magic trick for most voip lines.

[k2366]

I have been able to successfully send faxes using my Cisco PAP2T using the following settings:

Before changing any of these settings make note or your original ones.

1. On Line 1 - set network jitter buffer to very high;
2. Disable Change Jitter Buffer Adjustment;
3. Call waiting should be set to NO
4. 3-way calling should be set to NO
5. echo cancellor should be set to NO
6. silence suppression should be set to NO
7. preferred codec should be set to G711a

Change all these setting back to what they were after your done faxing. Also, a cool feature with Fongo is when someone sends
you a fax it should come through via your email (as a PDF) if you have voicemail set up to send you an email
notification with VM attachment.

Good luck!

Hey thanks for the settings
Tried them and it works great, I found the voice calls were not affected even though I never changed the settings back.