The person operating Global Maritime Distress and Safety System (GMDSS) equipment is required under the International Maritime Organisation, Safety of Life at Sea (IMO SOLAS) convention to hold a certificate to prove competences (knowledge and practical skills) to operate GMDSS equipment. In the maritime sector, operators can hold 1 of the following radio certificates:
- GOC (General Operator’s Certificate): required on SOLAS vessels operating also outside GMDSS Sea Area A1,
- ROC (Restricted Operator’s Certificate): required on SOLAS vessels operating only within GMDSS Sea Area A1,
- LRC (Long Range Certificate): required on non SOLAS vessels operating also outside GMDSS Sea Area A1,
- SRC (Short Range Certificate): required on non SOLAS vessels operating only within GMDSS Sea Area A1,
- VHF (Restricted radiotelephone operator's certificate (Very High Frequency): a certificate similar to SRC that proves only the competence to operate a VHF DSC radio - in some countries it is not recognised.
Certificates are issued by national agencies based on examination.