has used a PC or laptop will have used this ports without themselves knowing.
of the USB port goes back to the period of 1990s
where several connection interface exist such as serial port, parallel port, ps2, etc. With so many interfaces,
a typical user will need different cables for each separate connection.
USB(Universal Serial Bus) was created to standardize all
the different interfaces, hence the word “universal”
With the standardization of different interface, the USB
port has more tasks to complete - to increase their transfer rate between the host and devices connected to
USB started off
specification USB1.0 in 1994,
USB1.1, and finally
USB2.0 in 2000
transfer speed of the specification is as follows
As of writing,
USB3.0 Specification was in the midst of discussion and the transfer speed is rumored to be at
The increase in transfer speed was mainly meant for
transferring of data between devices. As USB hard disk expands in capacity, and users are demanding for better
video quality, naturally, video file sizes are increased. Thus the birth of USB3.0
The first commercial product released for USB flash
drives, commonly known as thumbdrive, in 2000. Back then, flash storage was at a measly 128mb. At time of
writing, 2009, 1.5TB (1,500GB or 1,500,000MB) already exists!
If we were to
transfer a single file of 5Gb on usb1.1 specs, on theory, we will need 3333s, which will take around 55min!! and
83s on a USB2.0 Specs.
Over the years, different companies develop different
interface for USB devices as well, which somehow defeats the purpose of standardizing a common interface.
However, the problem of different interface was not as serious as it was back in 1990s.
left to right:
male micro USB, male mini USB B-type, male B-type, female A-type, male A-type) shown
with a 5 cm scale.
USB cable was
able to carry power and to power up devices such as thumbdrive, webcams, external hard disk, usb speakers, etc.
However, power is capped at 5v, 100mA.
cables suffer from a “useful” distance. Meaning, the maximum length of a usb cable is capped at 5m. Should the
length be longer, the efficiency dropped and data may be corrupted.
For PCs with
limited USB ports, a hub, typically with 4 additional USB ports, may be purchased. This will indirectly increase
3 more USB ports on your computer. However, take note that the bandwidth and power of each port on the USB hub
will be reduced, as all its bandwidth and power are sourced from a USB port.
problems faced from using a USB hub, slower transfer rate and the inability to power up external 2.5” hard disk
as they require more power as compared to a usb webcam or usb speaker.
all to wrap up for the topic and history for USB. I hope that the above computer guide will assist you in having
a further understanding of USB history.
Source : S-Mall Pte Ltd