Pathway/iTS TCP and Terminal Programming Guide

Programming for Specific Terminals
Compaq NonStop™ Pathway/iTS TCP and Terminal Programming Guide—426751-001
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Using 6520 Terminals
Using 6520 Terminals
When communicating with 6520 terminals in the Pathway environment, you need to
consider:
•
The rules for controlling the screen mode
•
The rules for positioning the screen fields
Controlling the Screen Modes
The 6520 terminal has two screen modes, as shown in Table 3-3. You control which
screen mode is used by a SCREEN COBOL screen definition.
When running a SCREEN COBOL application on the 6520 terminal, the screen mode is
determined as follows:
•
If the screen definition is equal to or less than the column limit of 40, the 40-column
mode is used.
•
If the screen definition is in the column limit range of 41 through 80, the 80-column
mode is used.
•
If no screen size is specified, the 80-column mode is used.
Switching screen modes can decrease performance because the terminal memory is
cleared to spaces on every mode switch. For the best performance for your SCREEN
COBOL application, use the same screen mode for all the screens.
Positioning the Screen Fields
All nonliteral fields must reserve a blank character immediately before the field. For
example:
•
If a field is at line 2, column 2, and is one character long, then 2,1 and 2,2 are
reserved for the field. A second field cannot be at 2,3 because both fields would
attempt to use location 2,2.
•
A field cannot be at 1,1 because the character before 1,1 does not exist and thus
cannot be reserved.
Fields cannot wrap from the bottom to the top line of the screen.
The minimum separation between screen elements for the 6520 terminal is indicated in
Table 3-4
.
Table 3-3. Screen Modes for 6520 Terminals
Base Screen Size
Mode Lines Columns
40-column (80-column screen with double-wide characters) 1-24 1-40
80-column (80-column screen with standard characters) 1-24 41-80