sparkfun RTK Express Hook-Up Manual page 20

using a serial radio for your correction data, you can skip this part.
When powered on, the RTK Express will broadcast itself as either 'Express Rover-5556' or 'Express Base-5556'
depending on which state it is in. Discover and pair with this device from your phone or tablet. Once paired, open
SW Maps.
Note: 5522 is the last four digits of your unit's MAC address and will be unique to the device in front of you.
This is helpful in case there are multiple RTK Expresses within Bluetooth range. The MAC address for a RTK
Express is shown in the upper left corner of the display.
SW Maps with RTK Fix
MAC address 5522 is shown in the upper left corner