Multiple PRI (ISDN) cards on a single FreeSWITCH box

Where the number simultaneous calls are increasing many of you would like to scale up your FreeSWITCH/Asterisk system by increasing number of PRI/BRI lines to your system and for that, you would like to run more than one telephony card. 

I have successfully tested 3 cards on a single FreeSWITCH machine.

Here is a simple tutorial on how to achieve that (With reference to DAHDI. ofcourse you can use sangoma or any other manufacturer’s cards).

  1. Insert the card into your PCIe slot (as most of the cards today are PCIe compatible)
  2. Load the driver module specific for the cards.
    Now this step should be taken care of. Suppose you are using DAHDI as the driver interface, you have to find the name of the specific driver module for the particular card e.g. for digium 8-span card it’s “wct4xxp”, for single span “wcte12xp” . Now load the module(This step could be different for different OS platforms).
    Now if you are using different type of cards (of same manufacturer as I used) e.g. 8-span and 4-span, you will have to load modules for both the cards.
  3. After modules are loaded properly the cards can be detected by the system.
  4. Configure cards in system.conf (wrt dahdi). 
    If you are using 8+4 span card for example, configure 1-12 spans in system.conf and run dahdi configuration utility and the lines will be up if connected properly.
  5. Now the last step is to configure mod_freetdm. Configure 12 spans in the configuration files of mod_freetdm(refer wiki) and if done properly the system will be up and running.

If you find any issues reach me at gautamashish09[at]gmail.com