What Is a TTY Port?by George Townsend
Over the years, the meaning of the term "TTY port" has evolved from describing a physical connection on a computer to describing a virtual connection. Along the way, the term has always referred to the communication between a computer and a remote user.
The first computers were large, expensive machines located in air-conditioned rooms some distance from the people who used them. The connections to the remote users from a computer were provided by teletypewriters and the term TTY originally evolved as an acronym of sorts to refer to these devices.
TTY devices were originally connected by serial ports to the main computer, and if the remote user was in a different building or city, this would be accomplished using a computer modem. Originally, teletypewriters were electromechanical in nature and printed characters on rolls of paper. As the technology developed, smarter electronic devices with CRT displays began to replace the original devices, however, the term TTY stuck and was also used to describe these more-advanced computer terminals.
As of 2010, users each have their own desktop computer that is used to access other computers on a network. The term TTY is still used to describe this relationship. Since actual dedicated terminal devices are no longer used, the term "pseudo TTY" is now used to describe a "virtual" connection over a network from one computer to another in which one acts as a host and the other as a terminal. The updated acronym PTTY is often now used in place of TTY.