NCR 6932-2201-9090, Руководство пользователя

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Configuration 3-41
Double Key Error Detection
All the keys in 64 Key POS keyboard have a double key error detection capability which
generates an error tone when two or more keys are depressed within 18mS.
When Double Key Error Detection is enabled and two or more keys are detected within
an 18 millisecond period, the keyboard firmware will indicate an error condition in the
same manner as a Buffer Overflow (01 Hex). The multiple keys detected within the 18
millisecond period will be ignored by the keyboard and not sent to the host system.
Only the Buffer Overflow Indication will be sent to the system.
In case auto detection of double height/wide key is enabled, if two keys are depressed
with 18mS and those two keys position is a valid blocking key pair, the keyboard will not
generate an error tone, instead, the keyboard firmware regards this as a blocked key
which is a double height/wide key.
When Double Key Error Detection is disabled, the keyboard firmware will not perform
Double Key Error Detection and will transmit all key entries. This allows for system
diagnostic and configuration software to receive two key codes for double size keys for
initialization of the keyboard. Once the double size keys are defined, the configuration
software will then activate the double key error detection feature while programming
the keyboard for Blocking Keys.
Num Lock operation
When the keyboard is reset or powered up, the firmware send the NUM LOCK make
and break codes to the terminal during the initialization. The firmware then monitors
for the terminal to turn on the NUM LOCK indicator by using the Set/Reset Mode
Indicator command.
During normal operation, when a key on the numeric keypad is pressed, the keyboard
firmware examines the current state of the NUM LOCK and performs one of the
following:
• NUM LOCK Flag Clear —the firmware sends the NUM LOCK make and break
keycodes, and then sends the make code for the depressed numeric key to the host.
• NUM LOCK Flag Set —the firmware simply sends the make code for the numeric
key pressed without sending a NUM LOCK keycode.
The NUM LOCK make or break code is sent before the code for each key on the
numeric keypad until the NUM LOCK indicator is turned on by the terminal.