HP 262SA Reference Manual page 373

3276/78 Emulation Mode
APPLICATION PROGRAMS
An application program running on your host system interacts with each control unit and
display station. The program sets the format for the display screen and determines how
certain keys are interpreted and how the system responds to the operator. You should see the
appropriate manual for the implementation of any application program that you are using.
COMMANDS AND ORDERS
An application program interacts with your terminal through tCCommands" and cCOrders". The
control units in the 3270 system recognize four basic types of commands:
• Write Commands
• Read Commands
• Control Commands
• Sense Commands
Orders further define write operations.
NOTE: As Sense Commands are inapplicable for the models of the 3276 that HP emulates,
they receive no further treatment in this manual.
Commands
The HP 2625A supports three types of commands: Write Commands, Read Commands, and
Control Commands.
WRITE COMMANDS.
The HP 2625A supports three types of Write Commands that control
the writing of data to the display. A Write Control Character may supply additional informa-
tion.
• WRITE -This command transfers rCwrites") data from the host computer to the terminal.
• ERASE/WRITE - This commands erases the entire display before implementing the write
operation.
• ERASE/WRITE ALTERNATE -This command erases the entire display and sets the alter-
nate screen size before implementing the write operation. The normal rCdefault") screen
size is 24 lines by 80 characters. You may set an alternate screen size in the 3276/8
Configuration menu.
The WCC (Write Control Character) contains information associated with a Write Command.
The information shows whether to reset the keyboard, ring the bell, or reset the MDT
(Modified Data Tag) bits.
Refer to the IBM 3270 Information Display System Component Description manual for a
complete description of the sequence of bytes in the Write Command and the format for the
Write Control Character byte.
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