fxotune - automatically tune DAHDI FXO channels
fxotune -i [options] - detect mode
fxotune -d [ options ] - dump mode
fxotune -s - Startup mode
fxotune is a script that fine-tune parameters of the FXO modules of the
card. It has three modes of operation:
Detect mode (-i): it detects and tunes all the available FXO channels.
It writes settings to a configuration file (/etc/fxotune.conf) from
which it can be loaded (e.g: at startup) using -s .
Dump mode (-d): Runs detection on a single DAHDI channel, and just
dumps waveforms to fxotune_dump.vals is generated in the current
Startup mode (-s): fxotune just reads the settings from fxotune.conf
into the FXO modules.
You are advised to run fxotune on all FXO ports you have that support
it and that are connected. Note that the tunning is affected by e.g.
the physical parameters of the connection, and thus if it has been
radically changed, you may need to re-run fxotune.
This program only works for the Digium TDM400P/800P/2400P cards and
compatible and the Xorcom Astribank devices. Other cards (notably X100P
cards and clones) do not have the hardware to support such tuning.
The tuning process needs a clear line to do the tuning. In order to do
that, it runs in cycles of the following: sets the line off-hook, dials
a dial string (which should set the PSTN provider waiting for the next
digit), and then starts tuning. It has a limited ammount of time for
tuning before the PSTN gives up and gives a busy tone. So after a while
it hangs up and starts a new cycle.
fxotune has two operation modes: tune (-i) and set (-s). In the tune
mode it generates /etc/fxotune.conf, and in the set mode it merely
applies the parameters from fxotune.conf to device’s ports.
The following options below except -v (verbose) affect only the
detection process and hence apply only to the detect and dump modes.
In addition, to maintain compatibility with older versions of fxotune,
if in detect or dump mode there is a parameter with option before it,
it is considered to be the dialstring parameter (-n).
Start tuning from dahdi channel num. startdev: skip all
previous channels. By default starting from channel 1.
In dump mode (-d) this is the single channel that will be
Tune only up to dahdi channel num. stopdev: skip all previous
channels. By default stopping at channel 252.
In dump mode (-d) this parameter is ignored.
Time in seconds to wait after dialing the dial-string to get a
clear line. The default is 0. before
Time in seconds which states how long the PSTN will wait after
we dialed the dial-string until it starts giving a busy tone.
You can test this by connecting an analog phone to the line and
The default is 18 (18 seconds).
Digits to dial to the PSTN in order to get it stop its dialtone
and waiting for the next digit.
The default is "4" (sending just the digit 4). It should work in
most cases. Again, this can be tested by connecting a phone to
the PSTN line and dialing the dial-string.
This option allows using the older detection method used by
fxotune of Zaptel 1.2. use -t 1 for that older method. whereas
-t 2 (the default) uses the current method.
This option only applies to detect mode (-i).
Sets debugging on. The more v-s, the higher debug level.
Note that: -vv -v will actually set debug level to 1 instead of
The default: -1, for multitone waveform. Alternatively: a
frequency of a single tone.
This option only applies to dump mode (-d).
fxotune -i 9
if you need to dial 9 for an external line. If you always get a line,
you can simply use any digit.
Load settings from the last test. Used at startup.
The configuration file generated by fxotune in detect mode and
from which configuration is loaded when -s is used.
Running fxotune takes approximately a minute per port. If you wish to
only run fxotune for several ports, you can use the options -b and -e
to set a specific range of ports. Another useful trick is to actually
keep asterisk running, and only "destroy" the dahdi channels you wish
to tune (dahdi destroy channel NNN): other channels will be used by
Asterisk, and hence skipped. This can be useful if you have many FXO
ports that are not connected.
fxotune writes immediately to /etc/fxotune.conf so if you stop it half-
way, you may get a half-configured system. If you have already tuned
your FXO channels and wish to test-run fxotune again, you are advised
to backup /etc/fxotune.conf .
The default for -m is 18 seconds. This asusmes that you get a clear
line for at least 18 seconds. It is advised that you test that timeout
earlier by connecting a phone to the FXO line, dialing 4 (or whatever
dial string you put with -n) and see how much time of silence you have.
If you connect your device to a PSTN provider that is not in the US,
there is a similar operation you should apply before even getting to
fxotune: setting the opermode. The opermode sets a number of country-
specific parameters. For the Digium analog cards this is set through
the kernel module parameter ’opermode’ . For the Xorcom Astribank this
is set through the variable ’opermode’ in /etc/dahdi/xpp.conf . For
valid values of this parameter, see /usr/share/asterisk/init_fxo_modes
(FIXME: this has changed and will change. Tzafrir).
dahdi_cfg(8), dahdi_tool(8), dahdi_monitor(8), asterisk(8).
This manual page was written by Tzafrir Cohen
<firstname.lastname@example.org> Permission is granted to copy, distribute
and/or modify this document under the terms of the GNU General Public
License, Version 2 any later version published by the Free Software
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can be found in /usr/share/common-licenses/GPL.