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Appendix B:
KE-USB108 Input Interface
The KE-USB108 has 108 individual inputs, which are activated by
shorting them to the common Ground provided on the input headers.
Since these inputs are individual, they are completely separate, and
cannot produce "ghosting" as in a matrix application. The KE-USB108
inputs are debounced for the use of mechanical switches as input to the
header.
KE-USB108 Inputs may also be driven from logic gate outputs, provided
they do not drive voltage above the 5V supply on the unit. The logic
signals must produce an active logic low signal for the appropriate
amount of time as listed in Appendix A.
The recommended maximum cable length from the KE-USB108
input header to the input devices is 10 feet. The recommended
maximum cable length of the USB cable from the PC to the
KE-USB108 is 15 feet.
Note:
The KE-USB108 allows any number of the 108 inputs to be activated
simultaneously. The response to each input will be processed in the order
detected. For inputs defined as keystrokes a maximum of 62 keystrokes
may be in the pressed state at any one time. This restriction applies only
to keystrokes that are repeating. The KE-USB108 will ignore keystrokes
presses over the 62 keystroke limit.
KE-USB108 Header Connection
Ground
Input 1
Input 2
Electrical connection example
for switches to KE-USB108 inputs.
26
Pushbutton
Com
N.O.
Pushbutton
Com
N.O.
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