Noland Engineering - NMEA DX28 Dual Expander NMEA 0183Noland Engineering NMEA 0183 DX28 Dual Expander NSN 7025 01 606 7150 The DX28 has two optically isolated NMEA 0183 inputs which each drive four NMEA 0183(RS 422) outputs. Normally, the two channels (PRIMARY & AUXILIARY) are completely independent of each other and can therefore operate at different baud rates. In Autoswitch mode, however, a loss of PRIMARY data for 5 seconds automatically switches all 8 outputs to the AUXILIARY input. When the PRIMARY