USB-I/O Interface Adapter GPIO-24. Programmer's Reference Manual.
 6.2.5. GPIO_IN_EV_FALLING (0x04) – Sending events when input value changes from
logical "1" to "0" |  | 6.3. Electrical Characteristics of Digital Inputs  |
Events are sent when input value of the pin changes.
Byte 6: REPEAT is ignored and will be reset to 0.
If Byte 5: DEBOUNCE is non-zero, the event is sent only if input value of the pin is stable for a predefined period of time. The time period is defined in ms.
