| 摘要 |
A transformerless data access arrangement (DAA) device (200) facilitates data transfer between a high speed modem device and a central office telephone line. The DAA device (200) uses D/A and A/D converters in conjunction with a pair of nonlinear opto-couplers that function as an isolation barrier. The A/D converter converts an analog signal received from the phone line into a one-bit modulated digital signal. The digital signal is relayed by the nonlinear opto-couplers to a processor. A phone line supply voltage is regulated internally and used to power the DAA device (200). When the processor detects a ring signal on the phone line, the processor generates a control signal which places the A/D and D/A converters in idle mode while sending a caller ID directly to the processor.
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