Restrictions

TTY limitations impose the following restrictions on maps:

Maps that contain fields that wrap around from the bottom to the top of the screen are not supported. A map is not a wraparound map if only the cursor returns to the upper left from the lower right coordinate at runtime.
The last position on the screen is unavailable. For example, data cannot be mapped to or from the position 24,80 on a 24X80 screen.
Maps with overlapping fields are not supported.

The following restrictions should also be noted:

TTY keys that do not put control codes into the data stream (such as SHIFT/CLEAR and CTRL/Q) should not be used, since RHDCTAPR registers user activity according to the control codes it receives.
The online mapping compiler can only be run at a 3270-type terminal.
A map generated through either batch or the online mapping compiler can be displayed on TTY and 3270-type terminals under the following conditions:
- A map that is wider than a given screen can not display on that screen.
- A map can only display at a terminal if the screen size for the terminal is specified in the map-definition. A TTY usually has a size of 24X80.
- A map can only display at a TTY terminal if the existing device independence table for the TTY terminal is specified at the beginning of the terminal session.