| 摘要 |
The emergency circuit has an isolating transformer enabling power derivation without disruption. The fax machine includes a main power supply source (10) connected to the electrical mains (22) in order to provide power to enable the machine to pick up a telephone line (21) via an electrically isolating transformer (4). There is also an emergency power supply (20) which is able to derive power from the telephone line (21), enabling the telephone circuit (5) to establish connection with the telephone line. The emergency power supply includes an electrically isolating transformer (16) between the line (21) and the telephone circuit (5). The emergency power supply includes an inhibiting circuit, arranged to inhibit operation of this circuit when the mains supply is operating normally. |
