This document describes the Natural function-key assignments that are supported for terminal devices of the 975n series (types 974n, 975n and 976n).
In Natural, function keys serve to transfer data together with specific command/execution information to a program.
For terminal device types that only support the keys F1 to
F5, the programmable P keys (P1 to P20) are
used for this purpose. This means that these keys are assigned the function key
values PF1 to PF20 (in 3270 terminology).
The identification of the key pressed is made from Natural-loaded key assignments in connection with the send-key code F5. This allows the distinction of similar data types which were sent using DUE1. Using F5, Natural recognizes the function-key resolution and interprets the P-key value as a code. In the other instance the data are transferred to the executing program.
The loading of keys is controlled by terminal commands or from the
executing program using SET
CONTROL statements.
There are three types of modes for key assignment:
| Mode | Description |
|---|---|
KN
|
For terminal types 974n, 9750 -
9755, the literals %K1 to %K20 are assigned to the
keys (terminal command %KN or statement
SET CONTROL
'KN').
For terminal types 9756, 9758, 976n,
send-key codes |
KO |
The literals 01 to 20 and the send-key
code F5 are assigned to the keys (terminal command
%KO or
statement SET
CONTROL 'KO').
|
KS |
The literals A to T as well as the
send-key code F5 are assigned to the keys (terminal command
%KS or
statement SET
CONTROL 'KS').
|
In KS mode, a dummy field is generated in the last two
terminal positions of each output message. This field is used for receiving and
transferring the key value. Prior to data transfer the cursor is moved in this
field using the movement functions assigned to the keys.
If an N is specified after the respective terminal command
(that is, %KNN,
%KON or %KSN),
only the corresponding function-key mode is activated, but no values are loaded
to the P keys.
For all modes, cursor-position-dependent key processing, according to current assignment, can lead to differing results. For example, the help key, dependent on field assignment, can invoke either the global or local help processing for a particular field. Such functions should be controlled using PF21 to PF23 interpreted keys (F1 to F3).