GMDSS通信英语阅读修改版..doc

阅读理解 PASSAGE1. Basic description of DSC: DSC is basically a calling system .Each call consists of a “packet” of digitized information of one of four priorities : Distress , Urgency , Safety , Routine. Message can be routed to “all stations”, to an individual station or to a group of stations, using their Maritime Mobile Selective-call Identify code (MMSI):Distress messages are automatically broadcast to “All stations”. In addition to the MMSI of source and destination stations, information can be conveyed in the DSC message:For example, to aid the Rescue Service, the DSC Distress alert message is configured to contain the following: A\Ship’s identify (the nine digit MMSI) B\Time. C\ Nature of distress (in the form of standard code) D\Ship’s position.Where fitted ship’s officers should ensure they are fully conversant with the procedure for entering the necessary information into DSC equipment:At sea, unless provided automatically from a navigation system, ship’s position should be update at least once during each watch period. 1. At sea, if DSC equipment can’t get ship’s position message from a navigation system automatically, then the position message should be renewed _______. A. .at least every 4 hours: B. at least every 8 hours C.at least every 12 hours: D. at least every 24 hours. 2. According to the message, distress message can be received by _______. A. all stations: B. coast stations. C. ship stations: D. group of specified stations3. Each DSC “packet” have _______ priority(priorities) A. 1 B. 2 C. 3 D. 4 4. Which of the following statement is not true? A. A DSC message has a MMSI of source station. B. A DSC message has a MMSI of destination station. C. A DSC message has a name of source station. D. A DSC message also has other information for sending rounD. Passage2. The NAVTEX receiver is a Narrow Band Direct Printing (NBDP) device operating on the frequency 518Khz, (some equipment can also operate on 490Khz and 4209.5Khz), and is a vital