The present document states the minimum requirements for equipment to be used for generation, transmission and reception of Digital Selective Calling (DSC) for use on board ships. DSC is intended to be used in the Medium Frequency (MF), High Frequency (HF) and Very High Frequency (VHF) bands of the Maritime Mobile Service (MMS), for distress, urgency and safety communication and general communications. The present document is part 1 of a multi-part deliverable that covers the requirements to be fulfilled by: • DSC equipment integrated with a transmitter and/or a receiver; • DSC equipment not integrated with a transmitter and/or a receiver. These requirements include the relevant provisions of the ITU Radio Regulations [i.17] and Recommendations ITU-R M.493-15 [2], M.541-10 [3], M.689-3 [4] and M.1082-1 [5], the International Convention for the Safety Of Life At Sea (SOLAS) [i.16], and the relevant resolutions of the International Maritime Organization (IMO). Equipment for generation, transmission and reception of DSC designed according to the following equipment classes: • Class A: includes all the facilities defined in annex 1 of Recommendation ITU-R M.493-15 [2] and complies with the IMO Global Maritime Distress and Safety System (GMDSS) carriage requirements for MF/HF installations and/or VHF installations. • Class D: provides minimum facilities for VHF DSC distress, urgency and safety as well as routine calling and reception as recommended by IMO MSC/Circ.803 [i.2] for non-SOLAS vessels participating in the GMDSS. • Class E: provides minimum facilities for MF and/or HF DSC distress, urgency and safety as well as routine calling and reception as recommended by IMO MSC/Circ.803 [i.2] for non-SOLAS vessels participating in the GMDSS. • Class H: provides minimum facilities for handheld VHF DSC distress, urgency and safety as well as routine calling and reception as recommended by IMO MSC/Circ.803 [i.2] for non-SOLAS vessels participating in the GMDSS. • Class M: provides minimum facilities for VHF Man Overboard devices as defined in Recommendation ITU-R M.493-15 [2].