Once a port monitor detects a request, it sets whatever parameters are required to establish communication between the operating system and the device requesting service. Then the port monitor transfers control to other processes (for example, the login program) that provide the services needed.
There are two types of port monitors included in the Solaris 7 operating environment: ttymon and listen. The listen port monitor controls access to network services and handles remote print and file system requests. The ttymon port monitor provides access to the login services needed by modems and alphanumeric terminals.