FCDC-3 - Backwards compatibility
From Zenitel Wiki
- The FCDC-3 is not compatible with FCDC-1, FCDC-2 and TFIX stations/[Ex Access Panels] running software version 4.1.3.12 or older.
- The FCDC-3 is compatible with FCDC-1, FCDC-2 and TFIX stations/Ex Access Panels after these devices have been upgraded to software version 4.1.3.13 or newer.