Question 42F2

The maximum specified length for a passive USB 2.0 cable is 5 meters. This limitation is critical for maintaining signal integrity and ensuring proper power delivery. USB 2.0 operates at a high speed of 480 Mbps. Over longer cable lengths, signal degradation becomes a significant issue due to attenuation and increased capacitance, which can lead to data errors and timing skew. Furthermore, voltage drop over the cable's resistance can reduce the 5-volt power supply available to the connected peripheral, potentially causing it to malfunction or not operate at all. Beyond 5 meters, active extension cables or hubs are required to regenerate the signal and boost power, effectively creating new 5-meter segments. Options B, C, and D are incorrect because passive cables of those lengths would experience excessive signal loss and voltage drop, rendering the connection unreliable or non-functional. Understanding signal loss and impedance over transmission lines is a foundational concept applicable across various electronic communications, including amateur radio.