| 摘要 |
PROBLEM TO BE SOLVED: To allow a caller to easily use a function of individually calling an extension telephone terminal from an outside line.SOLUTION: An individual call telephone number list 13B that stores an individual call telephone number for individually calling an extension telephone terminal 17, is stored in a storage unit 13 for each extension telephone terminal 17. For example, when a connection is established between an extension telephone terminal 17A and a user telephone terminal 2 over an IP network 3, and when the call is transferred from the extension telephone terminal 17A to an extension telephone terminal 17B, an individual call telephone number of the extension telephone terminal 17B is acquired from the individual call telephone number list by a telephone number notification unit 15, and the individual call telephone number is transmitted to the user telephone terminal 2 over the IP network 3. |
