| 摘要 |
PROBLEM TO BE SOLVED: To provide a technique to match the states of line keys without depending upon a main device among a plurality of telephone terminals which belong to a telephone system to which a plurality of lines are allocated.SOLUTION: An IP telephone terminal 1 displays the state of the line used by the IP telephone terminal 1 itself on a line key corresponding to the line and transmits the state of the line and line key information including a key ID of the line key which corresponds to the line to other IP telephone terminal 1. Moreover, the IP telephone terminal 1 receives the line key information transmitted by the other IP telephone terminal 1, and displays the state of the line included in the line key information on the line key specified by the key ID which is included in the line key information. |
