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any other displayable key stoke – will be taken as an input in scan-code format.
any other non-displayable key stroke – will have no influence
ANSWER BACK CODE
Programming the answer back codes of the 6 position electronic key-lock is
also very easy as they are included in the keyboard programming with the locations
coded as “KLP”, “KL0”, “KL1”, “KL2”, “KL3” and “KL4” in the key-layout map of
page L1. The programmable keyboard will issue an answer back code to PC whenever
the 6 position electronic key is switched to a new position or when the keyboard
receives an “enquiry” code (E7h) from the PC or the PST system. A time delay as
determined in the configuration of the keyboard programming utility is adjustable by
“r” and “t” key presses, this time delay is useful to give only the answer back code of
the last position of control key when it is turned across several positions. Here are
some examples of sending this “enquiry” code in different languages:
Language Syntax
C outp (0x60, 0xE7)
BASIC out &H60, &H0E7
DEBUG o 60 E7
HARDWARE LIMITATION
In case of “multiple combination key” application which means pressing three
or more keys at the same time to obtain certain data output from the keyboard, there
could be some limitations inherent from the nature of keyboard structure. The CPU of
keyboard detects the contact between the “horizontal” and “vertical” lines for each
key press, recognizes which key is pressed and sends correspondent data to the host
computer. When there are many keys pressed at the same time, and the pattern of the
contacts coincides with some special relationship, there are chances that the CPU of
keyboard be confused about exactly which keys are pressed. The user may change the
locations of the key-definition to prevent this once such confusion happens.