Decrease Baud Rate and turning off ECM
Packet loss, jitter, and latency all add up to corrupt a fax transmission in VoIP env
and unfortunately also in Asterisk PBX.
When a fax machine determines that some data is lost, it will shut down the entire fax transmission, even though you would still have a workable document.
By slowing down the transmission speed up to 9600 bps, you’ll increase the probability that all the faxes will be transmitted or received correctly.
To slowing down the BAUD rate to 9600 bps you need to check the parameteres of the fax device. Continue reading
To begin you need to install Debian 8.1.
Critical step in the installation process.
When the installation process ask for “Some of you hardware needs non-free firmware – the missing firmware files are rtl_nic/rtl8168g-2.fw”, you need to dowload from Debian Packaged web site package named firmware-realtek (see linkografia), uncompress it to an USB stick (using 7zip for example): after that you can insert USB key in your Acer and continue with installation process.
My choice: Guided – use entire – all file in one partition
My choice: ssh server and standard system utilities
Root SSH Access
You need to permit root user to get via SSH in order to facilitate the configuration steps.
> sed -i 's/PermitRootLogin without-password/PermitRootLogin yes/' /etc/ssh/sshd_config
> service sshd restart
Fax in Voip Env….. Joy and pain….
In this post I’ll show how to configure Asterisk 13/FreePbx 12 to use T.38 Fax capabilities to receive fax using SpanDSP (FFA not work in Asterisk 13….).
IMHO when possible is better configure Asterisk Fax system to use T.38 when possible instead alaw or other codec.
To transmit fax you can see my post.
Asterisk Mail2Fax using FFA in poor man style ! (linkografia)
To install and configure SpanDSP you can read my post
Add Fax capabilities in Asterisk >=13 (linkografia) Continue reading
I have already mentioned before. In the path caller->called codecs can change several times, and every transformation can introduce distortion and delay.
To minimize fax issues all the legs involved must be using the same codec to avoid codec translation. It is really important the kind of codec: you must use in all the path alaw or ulaw ! Continue reading