NEC switch - Manual (Page 97)

User’s Manual U12978EJ3V0UD
97
CHAPTER 8 USB FUNCTION
8.1 USB Overview
The USB (Universal Serial Bus) is suitable for connecting personal computers and external devices such as audio
equipment, keyboards, pointing devices, and telephones. Two data transfer rates, 12 Mbps and 1.5 Mbps, are
provided.
Plug & Play can also be realized.
Figure 8-1 shows an example of USB connection to a desktop PC. The USB consists of the host controller
installed in the PC, hubs installed for port expansion and connection, and functions installed at bus ends. These
functions are called endpoints and are the data transfer destinations or data transfer sources in the USB.
Figure 8-1. USB Bus Topology (Desktop Type PC)
Host
Hub
Hub
RootHub
Hub
Hub
Function
(monitor)
Function
(modem)
Function
(keyboard)
Function
(mouse)
Function
(CD-ROM)
Function Function
Host (Root Tier)
Tier 1
Tier 2
Tier 3
Tier 4