CAS firmware can be configured using various '-c' and/or '-s' switches. These switches can be applied when downloading the firmware. Amongst other things, firmware configuration switches can be used to configure register signalling and line signalling.
The configuration switches appropriate to a particular firmware are described in the appropriate release notes (please read them before attempting to use the firmware). In some cases, the firmware release notes suggest some country specific switch settings that have been known to work for customers in the past.
If you are having problems configuring your firmware, please try and obtain a signalling specification (detailing - ABCD bits and the type of register signalling employed) from the exchange you are connecting to and contact Aculab support.