This is a connector that can be used to connect to the JTAG/TRACE pins of the EvoPrimer base board. It allow you to use the Trace and JTAG pins as inputs or outputs ( download EvoPrimer Virtual Comport - remapped GPIO JTAG).
Now you can use an RJ11 as your power connection(VCC 3V, GND) and a RJ45 for an 8 pin connector.
You can download the documents for details on how to make the connector work for your project.