| 摘要 |
PURPOSE:To execute easily a holding operation by providing a memory for storing a dial request state at every terminal, so that if the request requires no dial, even if a hooking time in its terminal is small, it is decided to be the holding operation. CONSTITUTION:In a usual state, the contents of a dial request state memory 5 are all in a state that a dial is necessary. When two sets of telephones 1, 1 become a call state corresponding to each telephone set, to a dial unnecessary state thereby. Accordingly, in this state, a hooking operation is executed by one telephone set 1, and when it is transmitted to the central control equipment together with a pulse width through a communication supervisory equipment 2, when the pulse width is within some prescribed width, it is discriminated to be a holding operation, in accordance with the contents of said dial request state memory 5, and a holding tone are sent out to the telephone set 1 of the side where the hooking operation is executed, and the telephone set of the other party of a call, respectively. |
