54 STAT.] INTER-AMERICAN-RADIO COMMUNICATIONS-DEC. 13 , 1937 2527 (27) FREQUENCY TOLERANCE: The frequency tolerance is the maximum permissible separation between the frequency assigned to a station and the actual frequency of emission. (28) POWER OF A RADIO TRANSMITTER: The power of a radio transmitter is the power supplied to the antenna. In the case of a modulated-wave transmitter, the power in the antenna shall be represented by two numbers, one indicating the power of the carrier supplied to the antenna and the other the actual maximum rate of modulation used. (29) AERONAUTICAL SERVICE: A radio service carried on between aircraft stations and land sta- tions, and by aircraft stations communicating among themselves. This term shall also apply to fixed and special radio services intended to insure the safety of aerial navigation. (30) FIXED SERVICE: A service carrying on radio communication of any kind between fixed points excluding broadcasting services and special services. (81) SPECIAL SERVICE: A telecommunication service carried on especially for the needs of a specific service of general interest and not open to public correspond- ence, such as: a service of radiobeacons, radio direction finding, time signals, regular meteorological bulletins, notices to navigators, press messages addressed to all, medical notices, medical consultations, standard frequencies, emissions for scientific purposes, etc. (32) TELEPHONE BROADCASTING SERVICE: A service carrying on the broadcasting of radiotelephone emissions primarily intended to be received by the general public. (83) VISUAL BROADCASTING SERVICE: A service carrying on the broadcasting of visual images, either fixed or moving, intended to be received by the general public primarily. (84) AMATEUR SERVICE: A radio service carried on between amateur stations. (86) AIR MOBILE SERVICE: A radio service carried on between aircraft carriers and by aircraft stations communicating among themselves. (86) GENERAL EXPERIMENTAL SERVICE: A radio service carried on by experimental stations engaged in re- search or development in the radio art. (87) POLICE SERVICE: The radio service carried on by provincial, state, or municipal police authorities for emergency services principally with mobile police units.
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