INT F1 - Common ISDN API(Application Program[ming] Interface) The defined set of calls which a program may make to interact with or request services of the operating system or environment under which it is running. Because the inputs and outputs of the calls are well-defined, a program using the API can continue using the identical calls even if the internal organization of the program providing the API changes. (CAPI) v2.0 - "CAPI_SET_SIGNAL" - SIGNAL HANDLING AL = 05h AH = CAPI version number * 10 (14h for v2.0) DX = application ID (see AH=01h) ES:BX -> signal handler or 0000h:0000h to disable SI:DI = parameter to pass to signal handler Return: AX = status (0000h,11xxh) (see #04070) Notes: the caller is required to provide at least 512 bytes of stack space the signal handler is called as though it were an interrupt, with interrupts disabled and DX,SI,DI set as they were when this function was called; the handler must preserve all registers and return with an IRET the signal handler may call CAPI_PUT_MESSAGE, CAPI_GET_MESSAGE, and CAPI_SET_SIGNAL SeeAlso: INT F1/AL=01h