BenQ PL460 Installation Handbook page 18

Term
Upstream
Downstream
Hub
Root hub
Speed (low-speed,
full-speed and high-
speed)
Active (self-
powered) device
Passive (bus-
powered) device
USB connectors and receptacles
USB connectors and receptacles are grouped into two types: Type-A and Type-B.
Type-A
Connect
Standard
Mini
Micro
Type-B
Connect
Standard
Mini
Micro
USB cable length
For each passive connection between a two USB devices, the maximum length for USB 3.0 is 3
meters, and the maximum length for USB 2.0 is 5 meters. To extend USB connection beyond
this length limit, an active extension cable has to be used to ensure stable signal transmission
and reliable power supply.
18 Display installation guide
The direction of data transmission from a USB function to a host or hub.
The direction of data transmission from a USB host or hub to a function.
A USB device that provides upstream connection (port) to a host and
downstream connections (ports) to multiple functions.
A USB host that also performs the functions of a hub.
Three different speeds are currently defined in the USB 2.0 specification:
• Low-speed: data transmission at 1.5Mbps
• Full-speed: data transmission at 12Mbps
• High-speed: data transmission at 480Mbps
The actual transmission speed is determined by the device with the
lower (or lowest) speed. For example, if a low-speed (1.5Mbps) USB
peripheral is connected to a high-speed (480Mbps) USB host, the
maximum transmission speed between these devices will be 1.5Mbps,
not 480Mbps.
A USB device that has it own power supply and can operate without the
power supplied by the USB host.
A USB device that does not have its own power supply and solely relies
on the power supplied by the USB host.
• Type-A receptacles are used as outputs from host systems
Recepta
and hubs.
or cle
• Type-A plugs are always oriented towards the host system
and mate with Type-A receptacles.
• Type-B receptacles are used as inputs to hubs or devices.
Recepta
• Type-B plugs are always oriented towards a USB hub or
or cle
device and mate with Type-B receptacles.
Description/explanation