Among the two command in UNIX operating system namely cu and ct which belong to Intermachine communication. If soemone can brief me about the two commands it would help me to have a better understanding on this.

Both cu and ct belong to Intermachine communication commands. Intermachine communication commands are one which is used for communicating between two machines.cu command is used to dial a phone number and there by attempts to make an interactive communication between two machines.ct command dials the phone number of a modem which is connected to a system and thus creates a login process and thereby attempts to make an interactive communication between two machines.So both cu and ct belong to Intermachine communication commands.