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Product Overview 1-11
Double Key Error Detection
The highlighted areas on the image below have a double key error detection capability
which generates an error tone when two or more keys are depressed within 18mS.
See Configuration on page 25 for information on how to enable or disable Double Key
Error Detection.
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.