INT 16 - Shamrock Software EMAIL - SPECIFY COMMAND-WORD FOR USER FUNCTION
AX = 4503h
DL = port number (01h = COM1)
DH = maximum execution time in clock ticks (00h = 5 seconds)
ES:BX -> ASCIZ string with new user command-word
Return: AX = 4D00h if EMAIL installed on specified port
Notes:  a single user command (consisting of only uppercase letters and digits)
may be defined, and remains valid until it is overwritten or the
EMAIL program terminates; the user command must be activated by
calling AX=4504h at least once.
an existing command word may be redefined with this function
SeeAlso: AX=4505h

See also: 164504

164503 - Shamrock Software EMAIL - SPECIFY COMMAND-WORD FOR USER FUNCTION