TN3270
TN3270 Configuration

TN3270 screen size is configurable.

The default screen size is 80x24, 80 columns by 24 lines, also known as a Model 2.

Changing TN3270 screen size to 132x27 is useful for viewing the z/OS system log and unix files with long lines

ISPF Settings, =0, Terminal Characteristics, Screen format must be 3, Max.

wc3270 (Windows)
File  > Session Wizard  > 2. Edit Session  > 4. Model Number  > 5. Model 5 has 27 rows and 132 columns

Vista TN3270 (Windows)
Start a New Terminal Session  > Terminal Model - select Mod 5
Options  > Options  > Display tab  > Select Mod 5

x3270 (Linux)
Options  > Screen Size  > Model 5 (132x27)

3270 Terminal Protocol

  • Existed more than a decade before the internet and HTML
  • Is text only and designed for speed
  • Capable of sending and receiving full screens (rows x columns) as the result enter
  • Has protected screen fields, will not accept typed input, and unprotected fields, will accept typed input
  • Tab key will tab to next unprotected field
  • Input screen may consist of many changes and instructional commands to be processed as a result of enter