Communication system using multiple types of communication modes, communication terminal, computer program, and communication method

A communication terminal capable of communicating with other communication terminals in one or more types of communication modes, the communication terminal comprising:

• a communication support unit that, in the case where a first-type communication mode of the communication terminal is used by a first user, accesses a management unit to specify communication address information corresponding to the first-type communication mode of a second communication terminal used by a second user,
• wherein the communication terminal communicates with the second communication terminal in the first-type communication mode using the specified communication address information;
• the first user is a user that used a second-type communication mode of a communication origin terminal prior to switching to the first-type communication mode of the communication terminal;
• the second user is a user that communicated with the first user using the second-type communication mode of a communication destination terminal prior to switching to the first-type communication mode of the communication terminal;
• and
• the management unit is a unit that holds management information expressing which type of communication mode corresponding to which communication address information is used by which user and by which communication terminal, and connection information including communication address information of one communication terminal that has communicated and communication address information of the other communication terminal,
• wherein in the case where information expressing that a user using the communication terminal is the first user is not included in the management information, the first user is specified for the communication terminal based on a location of the communication terminal as specified by a terminal location specification unit that specifies locations of communication terminals, and a location of each of the first and second users as specified by a user location specification unit that specifies locations of users.

A communication method in which a first communication terminal used by a first user or another communication terminal:

• communicating with a second communication terminal used by a second user or another communication terminal in a second-type communication mode prior to switching to using a first-type communication mode of the first communication terminal;
• and
• transmitting connection information including communication address information in the second-type communication mode of the first communication terminal or other communication terminal and communication address information in the second-type communication mode of the second communication terminal or other communication terminal to a management unit that holds management information expressing which type of communication mode corresponding to which communication address information is used by which user and by which communication terminal,
• the management unit managing the connection information;
• the first communication terminal accessing the management unit to specify communication address information corresponding to the first-type communication mode of the second communication terminal used by the second user in the case where the first-type communication mode of the first communication terminal is used by the first user;
• specifying communication address information based on an instance of communication address information within the connection information that has another instance of communication address information corresponding to the second-type communication mode used by the first user, and based on the management information;
• and
• communicating with the second communication terminal in the first-type communication mode using the specified communication address information,
• wherein in the case where information expressing that a user using the first communication terminal is the first user is not included in the management information, the first user is specified for the first communication terminal based on a location of the first communication terminal as specified by a terminal location specification unit that specifies locations of communication terminals, and a location of each of the first and second users as specified by a user location specification unit that specifies locations of users.