| 摘要 |
PURPOSE:To recognize immediately a holding state and to attain very easy usage by providing a voice switch, a holding tone transmission circuit and a holding tone transmission switch, using a switch to change over a microphone and the holding tone transmission circuit and connecting the holding tone transmission circuit to a speaker. CONSTITUTION:In order to prevent the voice of this side from being listened to the other party, SW contacts 12, 13, 14 are turned on, the SW contact 12 disconnects the output of an M6, and the output of the holding tone transmission circuit HTS11 is transmitted to the other party via TA8, TVS9, HYB2 and 2- wire line 1. The SW contact 13 transmits the output of the HTS11 to an S5 via an RA4. Thus, the opposite party and the own subscriber recognize that a loudspeaker telephone set is in holding by listening to the holding tone. Further, a CTL10 given a ground potential by the SW contact 14 controls the circuit that both the transmission and reception of the loudspeaker telephone set are set. This is a purpose the voice of the opposite party is listened to from the S5 when it is incoming during holding and the reception side is set even during the transmission of the holding tone. |
