486 Monitor's System Call Interface You can call up the Monitor utility programs by entering the system call: "INT 20 (dec)" with a Function Code in register and if required a Parameter Block Pointer in (See Table 6-4). NOTE "input" - Refers to the parameters required by the PROMs. You must supply it before typing the INT 20 request. "output"- Is the result returned to you from the PROM. The following Monitor system calls are supported. See Table 6-4. 6-12