When connecting to the GPS receiver, the Error 55 message appears, even after changing the settings to a free COM Port.
This error occurs when the COM Port is changed in ArcPad but the application has not been restarted.
Trimble's SkyPlot uses TSIP messages and should be set at COM 2. ArcPad uses NMEA and should be set to COM 3.
ArcPad may be trying to use the same COM Port as SkyPlot.