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Important Note Regarding FreeSwitch® and FreeTDM® Support

Support for FreeSwitch and FreeTDM for Sangoma telephony card products are no longer provided by Sangoma. All FreeSwitch drivers and applications are provided as-is with no warranty.  

Sangoma was previously involved in the FreeTDM and FreeSwitch projects, but has refocused its development efforts primarily on Asterisk-based platforms including FreePBX. The information on this page and other FreeSwitch- and FreeTDB-related pages on the Sangoma Wiki has been retained for historical and reference purposes, but should not be relied upon as reflecting Sangoma's current development efforts or support policies.


All I/O related parameters are set in freetdm.conf.


[span wanpipe <span name>]

name => freetdm
trunk_type => <trunk type>
group => <group name>
<channel type>-channel => <physical span number>:<channels> 

span name: 
any string as long as the span name used in freetdm.conf and in freetdm.conf.xml are the same
trunk type: possible values are: fxs, fxo

group name: any string.
channel type: possible values are: fxs, fxo
physical span number: This should match the TDMV_SPAN  parameter in your /etc/wanpipe/wanpipeN.conf
channels: Specify which timeslots within this physical span you want to use.



Unlike PRI and BRI, analog does not have signaling channels. So in this file, the user mentions which context will be assigned to which span.

<configuration name="freetdm.conf" description="FreeTDM Configuration">                 

<!-- General FreeTDM Configuration options -->

<param name="crash-on-assert" value="no" />



<!-- list of ANALOG spans -->

<span name="[span name]">

<!-- switch related parameters -->
<param name="dialplan" value="XML" />
<param name="context" value="default" /> 





Sample configuration files

Configuration Options

In freetdm.conf

  1. Sample FreeSWITCH analog Configuration file#Gains

In freetdm.conf.xml

  1. Sample FreeSWITCH analog Configuration file#Tonegroup

  2. Callerid

  3. Sample FreeSWITCH analog Configuration file#Callwaiting

  4. Sample FreeSWITCH analog Configuration file#Polarity reversal

  5. Sample FreeSWITCH analog Configuration file#Polarity delay

  6. Sample FreeSWITCH analog Configuration file#Enable analog option

  7. Digit timeout

  8. Max-digit





With the gain option, you can try to increase or decrease the signal strength

rxgain => X
txgain => Y

and Y can be positive or negative values



tonegroup is a two letter country code which the user can specify, to select the tone zone

<param name="tonegroup" value="tonegroup" />

tonegroup : us (United States), sg (Singapore), ru (Russia)



Enable/Disable callerid

<param name="enable-callerid" value="true" />



Enable/Disable callwaiting

<param name="callwaiting" value="true" />


Polarity reversal

Here there are several options for polarity reversal. The user can perform hangup on polarity reversal or answer on polarity reversal

Enable/Disable answer on polarity reversal

<param name="answer-polarity-reverse" value="true" />


Enable/Disable hangup on polarity reversal

<param name="hangup-polarity-reverse" value="true" />


Polarity delay

This option is for fxo only

<param name="polarity-delay" value="delay" />

delay: is the time in millisecond


Enable analog option

There are a few option which can be enabled on the analog by setting the following values 

<param name="enable-analog-option" value="option" />

option : call-swap, 3-way(three-way calling)


Digit Timeout

This option is for fxs only.

<param name="digit-timeout" value="timeout" />

timeout: amount of time allowed to input digits

Max Digit

This option is for fxs only.

<param name="max-digits" value="max_digit" />

max_digit:maximum of digit allowed


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