Automatic Connection System (ACS)

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Automatic connection system function on MF/HF (Class A and E) ACS aims to establish a communication link between ship station and ship/coast station by automatically selecting a working frequency.

Automatic Connection System (ACS) is currently being worked on in ITU-R WP 5B.

The necessary work is being done in the Revision of Recommendation ITU-R M.493-15, and in the Revision of Recommendation ITU-R M.541-10 and both these ITU-R Recommendations are referred to by Resolution MSC.512(105) in footnote 13. There is also ongoing work at ITU-R WP 5B for Preliminary Draft New Report ITU-R [ACS] currently titled “Operational procedures for both ship and coast stations for automatic connection system using digital selective calling communications in the MF and HF bands”.

It is described in the Revision of Recommendation ITU-R M.541-10 as: Automatic Connection System (ACS) means automatic connection function using DSC for shore-to-ship, ship-to-shore or ship-to-ship communication with the most appropriate working frequency (or channel) in the MF and HF bands of the maritime mobile service. The procedures for ACS using DSC communications on MF and HF are described in this annex 5 of Recommendation ITU-R M.541 (Once revisions are complete).