| 摘要 |
PURPOSE:To obtain the telephone terminal device which is easily moved and usable for a long period without any battery replacement by using an office power source effectively when it is usable and driving a service circuit and an automatic answering circuit. CONSTITUTION:When termination is waited for, neither a judgement part 29 nor a speech circuit 53 operates. A backup secondary battery 39 is connected to a feed line 50 through a diode 87 to back up a RAM 71 and a control part 40. Further, an auxiliary battery 37 also backs up them through a resistance 92 and a diode 95 as well as the backup secondary battery 39. When there is an incoming signal from a trunk line, the judgement part 29 operates with the electric power of the calling signal and monitors the states of the auxiliary battery 37 and backup secondary battery 39 to output information corresponding to the battery states. The operation during a telephone call is carried out by feeding electricity from the office power source. |
