Upon start-up the CXACUDSP.DLL library opens and initialises the Aculab call control boards ready to make and receive calls.       The order that the boards are opened is specified by a configuration file called ACUCFG.CFG whose path can be defined by the environment variable called ACUCFGDIR.       If the ACUCFGDIR environment variable is not set then the library will look in the current directory for the ACUCFG.CFG.

If the ACUCFG.CFG file is not found then the boards are opened in the order that they are found in the Aculab Configuration Tool (ACT), and which is the order returned by the acu_get_system_snapshot() function.   

The format of ACUCFG.CFG file is described here.

The order that the Prosody speech boards are opened is important since it defines the logical channel number that is used in many of the calls to the CXACUDSP.DLL functions.     Voice channels are numbered starting from 1 up to the maximum number of voice channels in the system.           For example in the following ACUCFG.CFG there are two modules each with 150 channels.    These will be assigned voice channel numbers 1 through to 300:

# One Prosody X card with 4 E1 ports and 2 DSP modules

board=189747

ports=0,1,2,3

modules=0:150,1:150

Note:  If  the number of voice channels is not specified in the ACUCFG.CFG file, or no ACUCFG.CFG file exists then the current version of the library will assume that there are 150 voice channels for every DSP fitted onto a Prosody X speech card and 60 voice channels for every DSP fitted onto the old Prosody cards.