The terminal emulator in tnz is called zti. There are various settings that impact the presentation of the 3270 terminal screen on the terminal controlling zti. Some of these can be found in colors and screen sizing. Some others are documented on this page.

Cursor

Zti, like other 3270 terminal emulators, keep track of an insert/replace mode. The mode determines whether a keyed character replaces the current one on the screen or gets inserted before it. The shape of the cursor can be used as an indication of the current mode. The following cursor shapes may be available in your controlling terminal:

1. Blinking block
2. Steady block
3. Blinking underline
4. Steady underline
5. Blinking bar
6. Steady bar

By default, zti will use 1 (blinking block) for insert mode and 3 (blinking underline) for replace mode. The capability for terminal emulators to handle these cursor styles varies. For instance, usability of a blinking underline cursor on an empty underlined field may not be very visible in some terminals. To customize the cursor style, environment variables can be used to set the desired styles. Here is an example to set variables that achieve the default settings:

export ZTI_CURSOR_INSERT=1
export ZTI_CURSOR_REPLACE=3

The values for the cursor styles correspond to DECSCUSR arguments. You may need to consult your terminal documentation for the supported values. The following links may be helpful in finding supported values:

• https://learn.microsoft.com/en-us/windows/console/console-virtual-terminal-sequences#cursor-shape
• https://terminalguide.namepad.de/seq/csi_sq_t_space
• https://iterm2.com/feature-reporting