# Directives

DEFTTY | Define Terminal Size

## Format

DEFTTY [(chan)]col,ln
Where:

chan | Channel or logical file number of the file to define as a terminal.
col | Default maximum number of columns for the terminal. This must be an integer value, range 0 to 255.
ln | Default maximum number of lines for the terminal. This must be an integer value, range 0 to 255.

#### Note:
The number of lines has an additional limit based on a maximum of 20,000 characters per window (i.e. the maximum number of lines is 20,000/col).

## Description

Use the DEFTTY directive to designate that the logical file number refers to a terminal. You can specify the default maximum lines and columns supported by the terminal. If you do not designate the file as a terminal, Windows and other mnemonics will not be supported.

## See Also

MNEMONIC Define File Command Sequence

## Examples

deftty (lfo)80,25