20-02-2016, 12:25 PM
You no doubt reached this thread in a hunt for a solution to why you are having difficulty Faxing on your new VOIP Phone System...
Faxing from you old Analogue Fax machine through your new Digital VOIP Phone System is no doubt giving you huge headaches and hit-and-miss to what numbers work and those that don't (simply hanging up when the remte Fax answers).
Without going into the details of the cause (there is a lot of technical guff out there on the Internet for your pleasurable reading) it is simply the case of Fax Data being corrupted as it is being converted from Analogue (for Fax Machine) to Digital (your VOIP System) then back to Analogue at the receiving end (the other Analogue Fax Machine).
No doubt too that you have stumbled upon the World's recomendation to drop the Fax Machine's Baud Rate down to 9600bps.
This slows the Fax conversation so that errors can be much more easily aknowledged and rectified during transmission.
In most cases you will see nearly a 100% acuracy in your Fax transmissions.
However, IF you are still having issues then there are a number possible causes.
I can ONLY speak/comment over our recent deployments using Asterisk PBXs - namely Yeastar PBX units like the SOHO, Standard and U-Series.
With these PBX Units you have the ability to adjust the T38 settings on the SIP Configuration.
You need to turn Error Correction OFF and force T38 Baud Rate down to 9600bps.
On your FXS (Analogue) Port of the PBX that your Fax Machine is connected to, drop the RX/TX Gain way back down to the lowest (which on Yeastar is 20%).
We battled at one site for weeks trying all sorts of settings on the Fax Machine itself including the mandatory forcing of Baud Rate to 9600bps to no avail.
The second we dropped the RX/TX Gain on the PBX everything (including all previously unfaxable numbers) began working.
Faxing from you old Analogue Fax machine through your new Digital VOIP Phone System is no doubt giving you huge headaches and hit-and-miss to what numbers work and those that don't (simply hanging up when the remte Fax answers).
Without going into the details of the cause (there is a lot of technical guff out there on the Internet for your pleasurable reading) it is simply the case of Fax Data being corrupted as it is being converted from Analogue (for Fax Machine) to Digital (your VOIP System) then back to Analogue at the receiving end (the other Analogue Fax Machine).
No doubt too that you have stumbled upon the World's recomendation to drop the Fax Machine's Baud Rate down to 9600bps.
This slows the Fax conversation so that errors can be much more easily aknowledged and rectified during transmission.
In most cases you will see nearly a 100% acuracy in your Fax transmissions.
However, IF you are still having issues then there are a number possible causes.
I can ONLY speak/comment over our recent deployments using Asterisk PBXs - namely Yeastar PBX units like the SOHO, Standard and U-Series.
With these PBX Units you have the ability to adjust the T38 settings on the SIP Configuration.
You need to turn Error Correction OFF and force T38 Baud Rate down to 9600bps.
On your FXS (Analogue) Port of the PBX that your Fax Machine is connected to, drop the RX/TX Gain way back down to the lowest (which on Yeastar is 20%).
We battled at one site for weeks trying all sorts of settings on the Fax Machine itself including the mandatory forcing of Baud Rate to 9600bps to no avail.
The second we dropped the RX/TX Gain on the PBX everything (including all previously unfaxable numbers) began working.
