The TEC file extension is associated with the TECO text editor for DEC PDP-10 mainframe computers. TEC file contains macro used by TECO. TECO (Tape Editor and COrrector, later Text Editor and COrrector) is the text editor developed in the 1963 for PDP-1 computers.
The TEC file extension is associated with ECkit (Text Encoding Conversion toolkit), a program used for conducting text conversions. TEC file saves the compiled version of a text mapping that was specified in a plain text.