|
The Computers Back Connector Panel
By Stephen Bucaro
Many people get very nervous when they have to move a computer or connect a device
to a computer because the back panel of a computer looks like a tangled mess of cables
and wires. It may appear to be a tangled mess, but the connectors on the back panel
actually conform to a standard layout. The current standard is called the "ATX form factor".
Looking at the back of your computer, you can see that it is divided into three
sections. The power supply is at the top, the connectors are in the middle, and the
expansion board slots are at the bottom.
Most connectors are polarized, permitting the cable to be plugged in only in the correct
direction. The keyboard and mouse use "PS2" connectors. The PS2 connectors are color-coded.
The purple connector is for the keyboard. The green connector is for the mouse.
Note: The PS2 type connector was invented by IBM for their model PS2 computers.
To plug in a keyboard or mouse cable, first firmly match the cable to the connector.
Rotate the cable until the connector keys match up. Then push the cable into the connector.
The parallel port, serial port, and video port all use "D" type connectors (DB-25M,
DB-9M and DB-15F respectively). These are called D connectors because of their shape,
which permits the cables to be plugged in only one way.
The serial port was originally used for the mouse and modem, but it was a real pain
to configure those ports. The serial port is now obsolete. The parallel port is
almost obsolete, although it is still required by some printers. Both of these ports
have been replaced by the USB (Universal Serial Bus) port.
A USB port is keyed so that a USB cable can be plugged in only one way. In my opinion,
they should have specified a connector that is visually polarized. The odds are 50/50,
but I always seem to have the cable facing the wrong way when I try to plug it in.
(The guy who choose the USB connector must be the same guy responsible for polarized
AC line cords, which I also always seem to have facing the wrong way.)
The audio jacks are the most confusing connectors on the back panel. Although the
jacks are sometimes color-coded, the devices that plug into them rarely are.
The green jack (audio out) is where you plug in your left speaker. The right speaker
plugs into a jack on the left speaker. The red jack is where you plug in your microphone.
The center jack (audio in) is where you plug in audio from another device, such a CD player.
Note: The audio jacks have identifying symbols stamped into the metal next to them.
Good luck reading those symbols.
The bottom part of the back panel has knock-outs that are removed for the installation
of expansion cards. The most common expansion card is the modem. Modem circuitry is
seldom built-in to the computers motherboard because modem technology changes so rapidly.
Modem cards have two connectors. A cable from your telephone wall socket goes into
one connector. A telephone can be plugged into the other connector. Which connector
is which is identified by symbols stamped on the expansion card's face-plate. Good
luck reading those symbols.
When you need to plug a cable into the connector panel on the back of your computer,
it may appear to be a tangled mess of cables and wires. But the connectors on the
back panel actually conform to a standard layout. Next time you need to deal with the
connector panel, just return to this article.
| 
Free Downloads
RSS Feed