[Freeswitch-users] Need help with FreeTDM config

David George david at harktech.com
Sat Apr 7 19:35:16 MSD 2012

I am writing an application that uses FreeTDM with a Digium TE-220 Dual 
T1 card.  I started by looking at the testanalog sample and found that I 
also needed to add ftdm_global_configuration after ftdm_global_init.  I 
am now able to place a call, but I get a segfault early on referencing 

I am using an Adtran TSU600e for a channel bank and have a mixture of 
FXS and FXO cards in it.  Right now I am just testing with a phone 
plugged into an FXS port configured for TANDEM_LS.  The T1 is configured 
AMI/D4 for channelized T1 with robbed bit signalling.  The T1 is up and 
I have no alarms.

There isn't a lot of information on the FreeSWITCH Wiki or on the 
Sangoma FreeTDM Wiki for T1 RBS.  There is one mention that I should use 
channel type of fxo-channel or fxs-channel for RBS ( 
http://wiki.freeswitch.org/wiki/FreeTDM ).  I saw another place that 
says to use em-channel, but it may be specific to running Dahdi on 
Sangoma cards ( http://wiki.sangoma.com/FreeSWITCH-Dahdi-Mode ).

I have tried both configurations, but have gotten further with the 
fxo-channel config than with the em-channel config.

With the channel set to fxo-channel I get a segfault when I place a call 
and the first sigmsg->channel is referenced.

I can open a Jira and add backtraces, but I wanted to check if I 
probably had a configuration issue first.

E&M configuration I tried:
[span zt tsu600e]
trunk_type => EM
em-channel => 1-4
;fxo-channel => 1-4
;fxs-channel => 5-6
;fxo-channel => 9-12

FXO config I tried:
[span zt tsu600e]
fxo-channel => 1-4

Channel 1-4 is really an FXS card.  I am using the reverse like I used 
to with Asterisk.  Not sure if it is correct or not.


David George
Hark Technologies

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