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) v1.1 - "API-GET-SERIAL-NUMBER"
	AH = F2h
	ES:BX -> 64-byte buffer for CAPI serial number
Return: ES:BX buffer filled with ASCIZA NUL-terminated ASCII string.	The ASCIZ string "ABC" consists of the four bytes 41h, 42h, 43h, and 00h.  Unless otherwise specified, maximum lengths given in the interrupt list do not include the terminating NUL. serial number (seven digits), empty
	      string if no serial number
Notes:	the caller is required to provide at least 512 bytes of stack space
SeeAlso: AH=01h,AH=F0h,AH=F1h,AH=FFh