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Block Data Transfer
STATUS DATA TRANSFER
The status request types are as follows:
• Primary and secondary status.
• Device status.
• Cursor position sensing (both absolute and relative).
• Command completion status
(S/F/U).
• Terminal identification.
• Terminal features.
These requests are all intiated by escape sequences, and they are all returned as fixed-length
strings of ASCII characters.
The ending character is the configured block terminator when in Block Page mode, otherwise
the ending is CR (LF).
SPECIAL MODES
Two modes, Auto Keyboard Lock and Send Cursor Position, are available for use under special
circumstances. Auto Keyboard Lock mode can be used when the terminal is used with the X.25
protocol, and Send Cursor Position mode can be used for combinations of terminal modes which
require that the cursor position be sent to the computer before the data transfer begins. Both
modes are accessible only through escape sequences.
Auto Keyboard Lock Mode
Use of the X.25 protocol in a network in which the terminal is connected requires that the block
of data sent is received and acted upon (in some way) before the terminal sends another data
block. To ensure this, Auto Keyboard Lock mode locks the terminal keyboard in a manner in
which the keyboard will normally be unlocked only by the receiving host.
Auto Keyboard Lock mode is accessible only by the following escape sequences:
Ec
&-
Ec
&-
K
o
K
Enable Auto Keyboard Lock mode
Disable Auto Keyboard Lock mode
When disabled (the default mode), the terminal will act as currently defined. When enabled,
the user-definable function keys which have been assigned the Transmit Only attribute and
the. key will leave it locked after the data transfer has taken place. The host computer can
then unlock the keyboard (with the
CCEc b"
sequence) when it is ready to receive more data.
NOTE: When the keyboard is unlocked, the keyboard input buffer is flushed, so that any data
in it is lost.
A soft reset on the terminal will unlock the keyboard, but will not affect Auto Keyboard Lock
mode.
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