Prevent theft and data leakage of your importan
Block All Devices
Block unauthorized devices such as USB flash drives, CDs/DVDs, non-system drives and network drives.
Block unauthorized devices such as USB flash drives, CDs/DVDs, non-system drives and network drives.
Prevent Data Leak
Put off access to confidential data using USB-Block’s patented password-protection security.
Put off access to confidential data using USB-Block’s patented password-protection security.
Protect Data Theft
Multi-layered security levels block all types of malicious devices, making data theft impossible.
Multi-layered security levels block all types of malicious devices, making data theft impossible.
Protect Data Loss
Data stays tamper-proof and hack-proof, making it immune from sophisticated hacking tools.
Data stays tamper-proof and hack-proof, making it immune from sophisticated hacking tools.
Copy Protection
Prevent plagiarism, illegal distribution and copying of your data, making it a valuable asset.
Prevent plagiarism, illegal distribution and copying of your data, making it a valuable asset.
Log Illegal Activity
Illegal Log activity monitors & records the names of unauthorized devices with time and date.
Illegal Log activity monitors & records the names of unauthorized devices with time and date.
Compatible
Works on all versions of Windows, for example Windows 2000/ XP
/ Vista / 7 / 8
ReliableWorks on all versions of Windows, for example Windows 2000/ XP
/ Vista / 7 / 8
t files, documents and source codes from devices like USB Drives, CD/DVD and network computers. You can white-list your own USB drives and devices. Whenever an unauthorized device is detected, a password prompt comes up.
A USB hub is a device that expands a single Universal Serial Bus (USB) port into several so that there are more ports available to connect devices to a host system.
USB hubs are often built into equipment such as computers, keyboards, monitors, or printers. When such a device has many USB ports, they all usually stem from one or two internal USB hubs rather than each port having independent USB circuitry.
Physically separate USB hubs come in a wide variety of form factors: from external boxes (looking similar to an Ethernet or network hub) connectible with a long cable, to small designs that can be directly plugged into a USB port (see the "compact design" picture). In the middle case, there are "short cable" hubs which typically use an integral 6-inch cable to slightly distance a small hub away from physical port congestion and of course increase the number of available ports.
Laptop computers may be equipped with many USB ports, but an external USB hub can consolidate several everyday devices (like a mouse and a printer) into a single hub to enable one-step attachment and removal of all the devices.
Physical layout
A USB network is built from USB hubs connected downstream to USB ports, which themselves may stem from USB hubs. USB hubs can extend a USB network to a maximum of 127 ports. The USB specification requires that bus-powered hubs may not be connected in series to other bus-powered hubs.
USB ports are often closely spaced. Consequently, plugging a device into one port may physically block an adjacent port, particularly when the plug is not part of a cable but is integral to a device such as a USB flash drive. A horizontal array of horizontal sockets may be easy to fabricate, but may cause only two out of four ports to be usable (depending on plug width).
Port arrays in which the port orientation is perpendicular to the array orientation generally have fewer blockage problems. External "Octopus" or "Squid" hubs (with each socket at the end of a very short cable maybe 2 inches long), or "star" hubs (with each port facing in a different direction, as pictured) avoid this problem completely.
Length limitations
USB cables are limited to 3 m for low-speed USB 1.1 devices. A hub can be used as an active USB repeater to extend cable length for up to 5 m lengths at a time. Active cables (specialized connector-embedded one-port hubs) perform the same function, but since they are strictly bus-powered, externally powered (non-bus-powered) USB hubs would likely be required for some of the segments.
Power
A bus-powered hub is a hub that draws all its power from the host computer's USB interface. It does not need a separate power connection. However, many devices require more power than this method can provide and will not work in this type of hub.
A USB's electric current is allocated in units of 100 mA up to a maximum total of 500 mA per port. Therefore a compliant bus powered hub can have no more than four downstream ports and cannot offer more than four 100 mA units of current in total to downstream devices (since the hub needs one unit for itself). If a device requires more units of current than the port it is plugged into can supply, the operating system usually reports this to the user.
In contrast, a self-powered hub is one that takes its power from an external power supply unit and can therefore provide full power (up to 500 mA) to every port. Many hubs can operate as either bus powered or self powered hubs.
However, there are many non-compliant hubs on the market which announce themselves to the host as self-powered despite really being bus-powered. Equally there are plenty of non-compliant devices that use more than 100 mA without announcing this fact (or indeed sometimes without identifying themselves as USB devices at all). These hubs and devices do allow more flexibility in the use of power (in particular many devices use far less than 100 mA and many USB ports can supply more than 500 mA before going into overload shut-off), but they are likely to make power problems harder to diagnose.
Some self-powered hubs do not supply enough power to drive a 500 mA load on every port. For example, many seven port hubs have a 1A power supply, when in fact seven ports could draw a maximum of 7 x 0.5 = 3.5A, plus power for the hub itself. Designers assume the user will most likely connect many low power devices and only one or two requiring a full 500 mA. On the other hand, the packaging for some self-powered hubs states explicitly how many of the ports can drive a 500 mA full load at once. For example the packaging on a seven-port hub might claim to support a maximum of four full-load devices.
Dynamic-powered hubs are hubs, which can work as bus-powered as well as self-powered hubs. They can automatically switch between modes depending on whether a separate power supply is available or not. While switching from bus-powered to self-powered operation does not necessarily require immediate renegotiations with the host, switching from self-powered to bus-powered operation may cause USB connections to be reset if connected devices previously requested more power than still available in bus-powered mode.
Speed
To allow high-speed (USB 2.0) devices to operate in their fastest mode all hubs between the devices and the computer must be high speed. High-speed devices should fall back to full-speed (USB 1.1) when plugged into a full-speed hub (or connected to an older full-speed computer port). While high-speed hubs can communicate at all device speeds, low and full-speed traffic is combined and segregated from high-speed traffic through a transaction translator. Each transaction translator segregates lower speed traffic into its own pool, essentially creating a virtual full-speed bus. Some designs use a single transaction translator, while other designs have multiple translators. Having multiple translators is a significant benefit when one connects multiple high-bandwidth full-speed devices.[1]
It is an important consideration that in common language (and often product marketing) USB 2.0 is used as synonymous with high-speed. However, because the USB 2.0 specification, which introduced high-speed, incorporates the USB 1.1 specification such that a USB 2.0 device is not required to operate at high speed, any compliant full-speed or low-speed device may still be labelled as a USB 2.0 device. Thus, not all USB 2.0 hubs operate at high-speed.
Speed of USB 3.0 hubs with USB 2.0 devices
With USB 3.0 hubs there is a significant caveat to be aware of when attaching USB 2.0 devices; all USB 3.0 hub implementations (as of early 2015) treat the USB 2 and USB 3 buses separately, USB 2.0 device traffic is not aggregated onto the 5Gbps USB 3.0 host connection. Hence performance in this case is the same as if using a USB 2.0 hub; the USB 2.0 devices all compete for the same 480Mbps USB 2.0 host bandwidth and the super-speed capability is not utilized.
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