A communications officer is a naval line officer responsible for supervising operation and maintenance of a warship's signal flags, signal lamps, and radio transmitters and receivers.
[1] In the United States Navy, communications officers are referred to as a COMMO.
In the Royal Canadian Navy, this role is filled by the Communication and Information Systems Officer (CISO).
This is a trained Naval Warfare Officer (NWO) who fulfils three roles at sea: Bridge Watchkeeper, divisional officer for the Naval Communicators, and custodian of the cryptographic keying material (COMSEC).
CISOs will generally have 3–5 years' experience at sea as watchkeepers, as well as a 4–5 month course focusing on communications systems equipment, policy, and procedure.