| 摘要 |
PROBLEM TO BE SOLVED: To properly process a number display signal, in the case of connecting a telephone set having provision or no provision for a number display service to a telephone communication unit such as a multi-function telephone set as an externally mounted telephone set. SOLUTION: An operation panel 13 designates whether an externally mounted telephone set 2 connected to an external terminal 2a of a multifunction telephone set 1 is provided with a caller telephone number display function. A call signal is received in succession to a caller telephone number notice signal from a telephone line network 20. When the externally mounted telephone set 2 is provided with a caller telephone number display function, the externally mounted telephone set 2 conducts reply processing with respect to the caller telephone number notice signal, and the multi-function telephone set 1 conducts no reply processing. Thus, a nonconformity, where the reply processing is conducted twice and the resulting signal is sent to the telephone line network 20 can be avoided. When the externally mounted telephone set 2 is not provided with the caller telephone number display function, only the call signal is sent to the externally mounted telephone set 2 and the caller telephone number display is made using multifunction telephone set 1.
|
