I am new to USB. I am studying the USB in a Nutshell Guide and the relevant parts of the USB2.0 spec.

As per what I have read, a max of 127 devices can be connected to a single bus. As only one host can be connected to a bus (save the on-the-go spec), I take it that 127 devices can be connected to a host.

However, on reading the WikiPedia page for USB Hub, it is written that a hub can extend the USB network to a max of 127 ports.

Does this mean that I can then have 127 x 127 devices attached to a single USB bus (read host)?


No. 127 peripheral devices on a single host. By "extend the usb network" it means that a hub takes a single upstream port, and extends it to 2~7 (typical, some hubs can do more by having multiple hub ICs) downstream ports. It still has a maximum of 127 on the bus.


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