Satellite communication and ground communication systems are the means of communication between ships and the outside world. In the work and life of the crew, they often need to communicate with each other, which requires a complete and convenient communication system to meet the needs of the crew. Ship internal communication refers to the transmission of all kinds of necessary information within the ship, which involves a wide range of aspects. At present, it mainly includes: marine program-controlled telephone system, marine acoustic telephone system, marine command telephone system, ship order broadcasting system, general alarm system, emergency bell system, ship mother clock system, monitoring alarm device and television monitoring system, etc. In terms of location and mode of communication, at least the telephone system between the bridge and the machine control room, between the control positions of the steering gear in the bridge and the steering gear cabin, between the bridge and the radio room, between the bridge and the fire central control room should be available at any time.
With the development of science and technology, local area network (LAN) has been installed on many large and super-large ships to realize paperless office among crew members, and it can also be classified as an in-ship communication system. In addition, it has become a trend to build seamless network connection between ship and shore by connecting intra-ship LAN or telephone network with shore communication network through satellite ship station and other facilities.