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| CAST | Chinese Academy of Space Technology (CN) | CB | Citizen Band | CCIR | Comité Consultatif International des Radiocommunications (ITU) | CCITT | Comité Consultatif International de Télégraph et des Télécommunications (ITU) | CCMS | Committee on Challenges of Modern Science (NATO) | CCSDS | Consultative Committee on Space Data Systems | CDMA | Code Division Multiple Access | CE | Conformité Européenne (label for conformity to
European Directives) | CENELEC | European Committee for Electrotechnical Standardization | CEPT | Conférence Européene des Postes et des Télécommunications | CERGA | Centre d'Etudes et de Recherches Géodynamiques et Astronomiques | CGMS | Coordination on Geostationary Meteorological Satellites | C/I | Carrier-to-intermodulation products | CICG | Centre International des Conférences Genève | CIE | Commission Internationale d'Eclairage | CIMO | Commission on Instruments and Methods of Observations (WMO) | CIRM | Committee International Radio Maritime | CISPR | International Special Commitee on Radio Interference | CITEL | Inter-American Conference on Telecommunications | (Conferencia Interamericana de Telecommunicaciones) | CMTT | Joint Study Group for Television and Sound Transmission | CNES | Centre National d'Etudes Spatiales (F) | CNET | Centre National d'Etudes des Télécommunications (F) | CNIE | Comision Nacional de Investigaciones Espaciales | CNR | Carrier-to-noise ratio | CNRS | Centre National de Recherches Scientifiques (F) | CODATA | Committee on Data for Science and Technology | COFDM | Coded Orthogonal Frequency Division Multiplex | COMSAT | Communications Satellite Corporation (USA) | COPUOS | UN Commission on the Peaceful Use of Outer Space | CORF | Commission on Radio Frequencies (NRC-USA) | COSPAR | Committee on Space Research | COSPAS | Russian system of Satellite Search and Rescue | COSTED | Committee on Science and Technology in Developing Countries | CPE | Customers premises equipment |
CPEM | Conference on Precision Electromagnetic Measurements | CPG | Conference Preparatory Group (CEPT) | CPM | Conference Preparatory Meeting (ITU) | CRAF | Committee on Radio Astronomical Frequencies (ESF) | CSA | Canadian Space Agency (CDN) | CSIRO | Commonwealth Scientific and Industrial Research Organization | CSTG | Commission for International Coordination of Space Techniques for Geodesy and Geodynamics | CT | Cordless Telephone | CTO | Commonwealth Telecommunications Organisation | CTR | Common Technical Regulation (ETSI) | CW | Continuous Wave | |