| 摘要 |
PROBLEM TO BE SOLVED: To improve the convenient properties of the cordless telephone system by improving the efficiency of the use of a radio channel even in the case of simultaneously using many extension line cordless telephone sets like a cordless key telephone system. SOLUTION: The electric field strength of radio waves received from cordless telephone sets 110a and 110b dedicated to extension lines is detected in extension line radio control parts 105a and 105b inside the main unit 102 of a key telephone system and at least two states of transmission output are set corresponding to the reception electric field strength. Thereafter, when a call is terminated from a public telephone line network 101 through an outside line control part 104a or 104b, the extension line radio control parts 105a and 105b set to the state of weak transmission output is made to execute a radio channel connection procedure. |
