You learn a little more if you actually hover over the icons in the "Features" section (which is very poorly disoverable, I scrolled past it and then back again and on a hunch tried hovering on the icons). You actually find out what it is on the "Specs" page. http://www.brck.com/specifications/

  The BRCK is a rugged, cloud managed, full-featured router 
  with built in failover and programmable GPIO expansion. 
  BRCK can connect to the internet through RJ47, GSM, Wifi 
  Bridge, as well as Ethernet Over USB via the GPIO 
  Breakout. It’s rugged build and cloud managed interface 
  make it ideal for “away teams”, monitoring systems in 
  remote locations, and businesses with challenging 
  infrastructure. BRCK’s GPIO breakout provides 20 pins for 
  digital and alaouge Read/Write as well as I2C, SPI and 
  UART. This, combined with BRCK’s Arduino Profile, make it 
  ideal for quickly connecting hardware to the Internet of 
  Things.

RJ47 is also a connector I'm not familiar with. According to this site http://www.accesscomms.com.au/reference/RJreference.htm it's for "Programmed data equipment connected to a key system where the registered terminal equipment is not compatible with electrical characteristics of tip and ring behind line circuit." which really doesn't clarify anything. Given that it's an 8 position jack, however, I think that they meant the same thing as "RJ45" or "Ethernet"; but they don't seem to be good at communicating this.