Radio

In the FIRST Robotics Competition and the [ FRC Archive], radio is one of the colloquial terms for the various wireless communication systems that robots have employed every year after the inaugural 1992 competition which used wired tethers. Since 2009 this has been accomplished using wifi routers with custom firmware, with

RNet

Motorola RNet radios were the wireless modem radios used for communication in the FIRST Robotics Competition from 1993 to 1999. Rnet radios establish a wireless serial communications link similar to a dial-up modem but over-the-air instead of phone lines.

In the 1990s, teams would be supplied RNets in the kit of parts, but these were collected before the beginning of competition and teams in the pits were required to use a tether cable and tether adaptor, a 9-pin serial cable with a null-modem adaptor inserted to swap over the transmit and receive lines to connect the driver station to the robot controller - this also functioned as a wired tether outside of competition. Teams would be given a radio on the same frequency as the one positioned in their driver station to plug into their robot for the match.

Gallery

• Additional photos on the FRC Archive
• 
  A pair of RNet radios [1]
• 
  The tether cable and adaptor setup [2]
• 
  The transmit side of the 1995 control system with RNet radio [3]

Modem Radios

In the era of the IFI Control System, competition-legal radios were given to teams which would work in conjunction with the robot controller and operator interface's team number settings to link together. At competition, operator-side radios were affixed to the inside of the driver station "glass". Tether cables for robot control were still required in the pits and a serial tether cable had to be used to connect a PC to the robot controller for uploading and debugging code. IFI offered a pair of Ewave Screamer wireless transceivers to upload and debug code wirelessly. A larger style of radio was used in 2007 and 2008. These radios operated at 900MHz with a total of 40 channels, 5 open and 35 competition-only.

Gallery

• Additional photos on the FRC Archive
• 
  An IFI modem radio [4]
• 
  IFI radios hanging on the driver station wall [5]