Analog modems operate over which voice band range?

Analog modems operate over the voice band range of 20 Hz to 20 kHz. This frequency range is crucial for the transmission of audio signals, which includes voice communication. Analog modems leverage this spectrum to encode and transmit data over telephone lines, converting digital data into analog signals that can be sent through traditional phone infrastructure.

This frequency range specifically corresponds to the part of the spectrum that is utilized for human voice communication, enabling modems to function effectively over conventional telephone lines. The modulation techniques used by the modems are designed to work within this bandwidth, providing a reliable means of data transmission.

Other ranges mentioned in the options do not align with the standards used for analog modem operation. For instance, a range extending 10 Hz to 20 MHz would surpass the capabilities of standard voice communication equipment and fall outside the normal operational parameters for analog modems. Similarly, the ranges of 30 Hz to 40 MHz and 40 Hz to 40 kHz either exceed or do not adequately cover the essential bandwidth needed for effective analog signal transmission over phone lines.