I have one old system with freepbx that uses two ISDN cards. One card connect server to one telephone line and the other connects the server and a gsm module with mobile sim card.
The ISDN cards used are Concetronic c128i (info link).
Anyone knows of this cards are compatible with the current version of asterisk/freepbx? There is any guide to install this type of cards?
In the case of not being compatible what card you recommend to buy to replace this ones?