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How many NMEA devices can a single output drive?

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Whilst the 6 outputs of the NBF-2 are capable of driving up to 60 NMEA 0183 instruments, to maintain the galvanic isolation between each of the NMEA devices, it is recommended to use only one NMEA device per NMEA output.

If all the NMEA 0183 devices connected to a particular NMEA output are proven to have a correct NMEA 0183 opto-isolated input, then it is possible to connect one NBF-2 output to multiple NMEA devices and still maintain galvanic isolation. However, this is the only condition where multiple NMEA 0183 devices per NBF-2 output is recommended.

When using multiple NMEA devices per output, the exact number possible will depend on the total cable length, cable quality, and instrument inputs. Longer total cable lengths, poor cable resistance and capacitance, and device inputs not meeting the NMEA 0183 specifications (stipulating a maximum 2 mA drain) will reduce the maximum number of devices drivable.