# Terminal Device Definition (TERMDEV.E)
Read Time: 1 minute(s)
TERMDEV.E maintains the information used by the system to support various terminal types. The ASCII character sequences that are used by various terminals to display video, color and line graphics are different from one manufacturer to another. The sequence of characters transmitted to the host when function and navigation keys are pressed also varies. TERMDEV.E provides a way of defining these codes in a consistent manner so that the application program can be wriiten using one set of instructions that will produce the desired result on many different types of terminals.
One of the records defined in this file is called WINDOWS. This record is associated with the M3 client program and should not be altered.
Frequency of Use
Anytime a new terminal type needs to be introduced to the system.
Setup of the TERM.CONTROL record.