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Oxford Technical Solutions
Digital inputs and outputs
Table 20 describes each of the signals on the digital I/O connector J5 of the 14C0038X
user cable. A more detailed explanation of each signal can be found below.
Table 20. Digital I/O signals
1PPS output
The 1PPS (J5-1) output is a pulse generated by the GNSS receiver. The output is active even
when the GNSS receiver has no valid position measurement. The falling edge of the pulse is
the exact transition from one second to the next in GPS time. The pulse is low for 1 ms, then
high for 999 ms and repeats every second. The output is a low-voltage CMOS output, with
0.8 V or less representing a low and 2.4 V or more representing a high. No more than 10 mA
should be drawn from this output.
Figure 14. 1PPS waveform
