| 摘要 |
PCT No. PCT/GB93/01048 Sec. 371 Date Dec. 20, 1994 Sec. 102(e) Date Dec. 20, 1994 PCT Filed May 21, 1993 PCT Pub. No. WO93/25037 PCT Pub. Date Dec. 9, 1993A telephone line power strip-off circuit includes a low loss polarity guard sub-circuit, a low loss line seize sub-circuit, a low loss speech transformer sub-circuit and a high efficiency switched mode power supply which has an output voltage less than the input voltage, arranged to recover 80% approximately of the power presented to the terminals of the phone.
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