Information on configuring and fitting internal USB cables
These pages provide the basic information you will need when fitting your USB cable.
We receive lots of questions from new users who are not sure how USB pin
headers are used and why some USB devices have 4/5 pin connectors
whilst others have 8,9 or 10 pins.
This pages gives a brief explaination of the way that USB devices are connected to
the USB pin header on the motherboard.
If you
want to skip this basic introduction and move on to the fitting instructions page
click here
Motherboard style USB pin header connectors
Internal USB devices connect to the motherboard using 4 wires.
These wires are normally red, white, green and black. Two wires
(red and black) are used to provide power to the USB device.
The other two wires (white and green) are used to transmit
data between the motherboard and the device.
The 4 wires in the USB cable can be connected to the USB
pin header found on most modern motherboards. This pin header
is designed to support two independent USB devices. The header
is usually two rows of 4 or 5 pins. Each row of pins is normally
associated with a separate device as shown in the picture below.
When installing USB devices a separate cable can be
connected to each row of the USB pin header. Using separate
cables allows you to place your devices at different locations
in the computer case, for example in different drive bays.
Note each row of pins on the USB pin header works in exactly the same way
as the standard USB A sockets found at the rear of your motherboard. The only
difference is the way that the cable is connected to the motherboard.
The USB
pin header on the motherboard is the equivalent of
TWO standard USB A sockets.
USB Device connectors with 4 or 5 pins
If your device uses a pin header this will normally be a single row of 4 or 5 pins.
These pins are normally connected by the USB cable to one row of pins on the
motherboard USB header as shown in the picture below. Note that the device
only uses one row of pins on the motherboard header leaving the other free for
connecting a second USB device.
If you do not have a free USB pin header on your motherboard you can use
one of our adaptor cables to connect the device to a standard USB A
socket. See the section at the bottom of this page.
USB Device connectors with 8 9 or 10 pins
Sometimes manufacturers will build two separate USB devices
into a single unit. A common example of this is a card reader
that also has a front panel USB port. In this case the unit
will have a connector that has two rows of 4 or 5 pins.
Although, the two USB devices are both contained within the
same unit, the devices themselves are independent. Each device
needs its own separate connection to the motherboard USB header.
Normally the top row of pins on the device connector will be
for one device in the unit and the bottom row of pins will
provide the connector for the other device. The picture below
shows an example of a unit with a card reader + front panel USB
port. This unit has a 9 pin connector.
These devices can also be connected to standard USB A sockets if
you do not have a free pin header available on your motherboard See below.
Using adaptor cables
Most internal USB devices can be installed using a cable with pin header style
connectors at both ends. There are some cases when you might need to use an adaptor
cable. The most common problems are:-
You do not have a free USB pin header available on the motherboard.
Your devices use standard USB B or mini-b sockets rather than pin header connectors.
Your device is a memory stick or some other device that plugs directly into a USB A port.
These problems can be solved by choosing a suitable adaptor cable. All you need to do
is decide how you want the cable to connect to your motherboard and device.
The options for connecting to the motherboard are :
Using a cable that connects to a USB pin header.
Using a cable that plugs into a standard USB A socket.
The options for connecting to a device are :
Using a cable that connects to a USB pin header.
Using a cable that plugs into a standard USB B socket.
Using a cable that plugs into a standard USB mini B socket.
To select an adaptor cable you simply need to choose a cable that
has the appropriate connectors at each end of the cable.
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