Patent ID: 7843941

Claim:
A communication system comprising: a plurality of communication terminals; and a server that can connect to and communicate with the plurality of communication terminals, wherein the server includes: a first communication section to connect to and communicates with the plurality of communication terminals; a storage section to store a plurality of connection patterns, each connection pattern indicating timings at which a communication terminal operating according to the connection pattern will access the server, each of the timings being a multiple of a unit time by an integer less than or equal to a threshold value; a pattern selection section to select one of the connection patterns from the storage section; and a first control section to control the first communication section to transmit the connection pattern selected by the pattern selection section to a communication terminal to which the first communication section connects; wherein each communication terminal includes: a second communication section to connect to and communicates with the server; and a second control section to control the second communication section to connect to the server at timing indicated in the connection pattern received by the second communication section; and wherein: the first control section of the server controls, when connected to a first communication terminal through the first communication section at a particular timing indicated in the connection pattern, the first communication section to transmit an amount of communication data determined based on the integer of the particular timing by multiplying the integer by a unit data amount to yield the amount of the communication data; the second communication section of the first communication terminal receives the communication data from the server; the first control section of the server adds, when the communication data includes emergency information, a tag to a portion of the communication data that includes the emergency information; the second control section of each of the plurality of communication terminal gives, when the communication data transmitted from the server includes the tag, priority to the portion attached to the tag; the storage section of the server stores a plurality of emergency patterns each of which indicates timings at which the communication terminals will access the server in case of emergency, the intervals of the timings of the emergency patterns being shorter than that of the connection pattern; the pattern selection section selects, when being connected to a communication terminal through the first communication section in case of emergency, one of the emergency patterns from the storage section; and the first control section controls the first communication section to transmit the emergency pattern selected by the pattern selection section to the communication terminal to which the first communication section connects.