Digi 90000278_B - Manual (Page 17)

Digi One EM Hardware Reference 17
Power Jack (P7)
The power jack accepts 5 volts DC +/- 5% from a regulated
power supply. The development board is polarity sensitive.
The +5 volts is assumed to be the center contact on
connector, and the ground is the outside of the connector
barrel, as shown in the following figure.