This paper presents an overview of the CNS / ATM (Communication, Navigation, Surveillance / Air Traffic Management) concept as introduced in the early nineties based on ICAO recommendations. Special emphasis is given to the different VHF Data Link (VDL) technologies. The VDL technologies can be used to support air traffic services, such as Automatic Dependent Surveillance (ADS), Controller Pilot Data Link Communication (CPDLC), and Data Link Flight Information Services (DFIS). For reference, the paper also presents the CNS systems currently used in Colombia to provide air navigation services. This allows analyzing the advantages and disadvantages of the introduction of the CNS/ATM concept. For comparison between the current system and the proposed CNS/ATM concept, it is important to take into account the special geographic and air-traffic conditions of the country. Finally, this paper reports about the first implementation of data link communications in Colombia. At El Dorado International Airport in Bogotá city the Departure Clearance (DCL) service has been introduced as first communication service based on data link. This is the first step of CNS/ATM introduction within the Air Navigation Plan of the Colombian Special Administrative Unit of Civil Aviation (UAEAC) the Colombian aviation authority.