| 摘要 |
A cordless remote telephone unit communicates with a telephone line through a stationary self-powered base unit. The base unit is not plugged into an electrical household receptacle and is therefore completely portable to any location having a telephone jack. The remote unit is portable to any location within the radio range of the base unit. The base unit does not require a household electrical receptacle because non-rechargable batteries are used in the base and remote units, so there is no need for a battery charger. Moreover, power consumption is minimized when the system is idle by cycling the battery power in both the remote and base units. As communication begins, continuous battery power is proved in place of the cycled power in the base unit in reponse to receiving from the remote unit a 5 KHz activation tone, a security code and a 22 Hz pilot tone, or in response to a ring received from the telephone line. After communication is established between the two units, the base unit derives reliable power through its hook switch directly from the telephone line using a power regulator suited for the purpose, further reducing power demand on the batteries. Power cycling in the remote unit is replaced by continuous battery power in response to receiving from the base unit a ring tone generated by the base unit ring detector, followed by a security code, or whenever the remote unit hand set is picked up by the user. In one embodiment of the invention, the remote unit handset is connected to a remote unit chassis by a cord, and the remote unit radio receiver and radio transmitter circuits use the cord as their antenna. |
