1、ITU-R RECMN*M= LOBO 94 4855232 0523bL5 632 = 158 Rec. ITU-R M.1080 RECOMMENDATION ITU-R M. 1080 DIGITAL SELECTIVE CALLING SYSTEM ENHANCEMENT FOR MULTIPLE EQUIPMENT INSTALLATIONS (Question ITU-R 9/8) ( 1994) The ITU Radiocommunication Assembly, considering that Recommendation ITU-R M.493-5, 9 5.2 has
2、 recommended that the Xlo digit of the DSC address always a) be the figure O and is reserved for future use; b) c) vessel; d) the same MMSI all respond simultaneously; e) accordance with this Recommendation for multiple installations on a vessel; f) the problem stated in 9 d); g) that the optional c
3、apability in 0 e) can be implemented in a manner that will not derogate the normal functioning of other DSC operations or create incompatibilities with older DSC equipment where this capability is not employed, that a need has arisen for multiple DSC radios to be installed on a single vessel; that v
4、arious administrations only issue one MMSI according to Appendix 43 of the Radio Regulations to any that if only a single MMSI is assigned to a vessel with multiple DSC radios a conflict results when radios with that the Xlo digit in the DSC address be reserved for ship owners and installers to assi
5、gn as required in that the capability in 5 e) allows for an additional level of selective calling within the vessel itself which solves recommends that where there is a need for multiple installations of DSC equipment on a vessel, that they use equipment 1. designed with an expanded address as defin
6、ed in Annex 1. ANNEX 1 Technical characteristics of an enhancement of the digital selective calling system address for multiple radio equipment installations on the same vessel 1. General 1.1 except as noted in this Annex. 1.2 Implementation of the expanded address is optional. The content of the la
7、st address digit shall be the number O if this Recommendation is not implemented. In such cases, this equipment has three possible ways to treat calls received with Xlo not equal to zero. These are: decode the tenth digit, ignoring that Xlo has a non-zero value and acknowledge the call with the tent
8、h digit set to the same non-zero value (this method will also comply with equipment designed in accordance with this Recommendation); ignore the tenth digit and acknowledge the call with the tenth digit set to zero, the expected value. It should be noted that in this case the acknowledgement is rout
9、ed to the primary installation aboard the vessel; decode the tenth digit and since the tenth digit was expected to be set to zero, reject the call. All DSC sequences must utilize all technical characteristics as outlined in Recommendation ITU-R M.493 - - - COPYRIGHT International Telecommunications
10、Union/ITU RadiocommunicationsLicensed by Information Handling Services ITU-R RECflN*M. 3080 74 I 48552L2 0523636 579 = Rec. ITU-R M.1080 159 2. Technical format of the enhanced address 2.1 the DSC station shall be in accordance with 5 5.2 of Recommendation ITU-R M.493 Annex 1 except for the followin
11、g: 2.1.1 shipment. 2.1.2 2.1.3 which the ship is normally navigated. 2.1.4 That optionally, users can set the Xlo to any number 1 to 9 for additional radio equipment installed on the same vessel for making routine calls. It should not be possible for the user to accidentally set the Xlo digit to a n
12、on-zero value. This can be accomplished by prompts so that the user clearly understands that this action will change the tenth digit of the address. In order to take advantage of this Recommendation, the Xlo digit must be user programmable. The address of That the Xlo digit be user programmable and
13、the manufacturer shall set this digit to zero as a default for That the Xlo digit be used to differentiate various radio installations installed on the same vessel. That the Xlo always be set to zero on the primary radio installation, i.e. the radio installed at the position from COPYRIGHT International Telecommunications Union/ITU RadiocommunicationsLicensed by Information Handling Services
