ITPEC FE Subject A April 2024 Question 10
ITPEC FE Subject A April 2024 — Question 10 of 60
USB Device Addressing — USB supports up to 127 peripheral devices per host controller.
USB uses 7-bit addressing → 2^7 = 128 addresses, minus 1 for the host = 127 devices.
Devices connect through USB hubs in a tiered-star topology.
Why not others:
- (a) DisplayPort — video output, supports daisy-chaining only a few monitors
- (b) HDMI — video/audio output, one display per port
- (c) SATA — internal storage interface, point-to-point (one device per port)
Key rule: USB = 127 devices max. Remember: 7-bit address space minus 1 for the host.
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