This part of IEC 1097 specifies the performance requirements, technical characteristics, operational requirements and methods of testing of shipborne DSC equipment for use with MF, MF/HF and VHF installations in the GMDSS as required by Chapter IV of the 1988 amendments to the 1974 International Convention for Safety of Life at Sea (SOLAS) and is associated with IEC 945: 1994 (Shipborne radio equipment forming part of the global maritime distress and safety system and marine navigational equipment). When a requirement in this standard is different from IEC 945, the requirement in this standard shall take precedence. This standard incorporates applicable pa rts of the performance standards of IMO Resolutions A.609(15), A.610(15) and A.613(15) (DSC facilities for VHF, MF and MF/HF radio installations), the provisions of the ITU Radio Regulations, the technical characteristics of DSC equipment and the operational procedures for its use contained in CCIR Recommendations 493, 541, 689 and 821, and takes into account the general requirements contained in IMO Resolution A.694(17). For integrated equipment this standard specifies the requirements and methods of testing of the DSC part only. The RF part of the MF, MF/HF and VHF installations should meet the requirements of the respective standards in the IEC 1097 series. NOTES 1 All text whose meaning is identical to that in IMO Resolutions A.609(15), A.610(15) and A.613(15) and to that in CCIR Recommendations 493, 541, 689 and 821 is printed in italics and is prefixed by references (609..., 493..., 541... , 689... and 821... respectively) in brackets. 2 The classes of DSC equipment which are applicable to the stated SOLAS Regulations, IMO Resolutions and CCIR Recommendations are: (493 11,1) Class A equipment, which includes all of the facilities defined in Annex I of CCIR Recommendation 493, shall comply with the IMO GMDSS carriage requirements for MF/HF installations; (493 11,1) Class B equipment providing minimum facilities for equipment on ships not required to use Class A equipment and complying with the minimum IMO GMDSS carriage requirements for MF and/or VHF installations. Note also that this standard includes non-SOLAS options e.g. (493 11,1) Class C equipment, which is intended to provide DSC distress alerting giving ships identification only. (609 11.1 footnote) Class A or B DSC equipment conforming to CCIR Recommendation 493 shall be used to meet the IMO GMDSS carriage requirement.