The Communication and Information Systems Groups (Gp CIS), known until 2002 as the Transmission Troops or TTr (Dutch: Transmissietroepen, French: Troupes de Transmissions), are the military communications units of the Land Component of the Belgian Armed Forces.
Each brigade headquarters was also supported by its own HQ company that included a Transmission platoon.
In 2002, the brigade headquarters Transmission platoons were disbanded, and the independent Transmission units transformed into Groups CIS (Gp CIS).
On November 22, 2018, the Medium Brigade was restructured into the Motorized Brigade that included both the 4th Group CIS and 10th Group CIS.
The 6th Group CIS was integrated into the Special Operations Regiment (SOR).