Home Audio/Video Connections
Glossary
5.1-channel, 6.1-channel, and
7.1-channel inputs
These preamp-level analog
inputs can be found on the back panels of some home
theater receivers. A 5.1 input features jacks for 6
channels: left front, right front, center channel, left
surround, right surround, and subwoofer (sometimes
called "LFE" or "Low-Frequency Effects"). Because the
LFE channel carries a limited range of frequencies, it's
the ".1" in 5.1. A 6.1 input features the same jacks as
a 5.1 input, but adds a back surround jack; a 7.1 input
adds two back surround jacks.
Any of these
multichannel inputs allow you to hook up a separate
5.1-channel surround sound (Dolby® Digital, DTS®)
decoder, such as those built into some DVD players. You
can also use these inputs with newer, cutting-edge
5.1-channel music sources like DVD-Audio and SACD
players. The extra jack(s) in 6.1 and 7.1 inputs have no
current functionality unless you happen to be using a
separate surround preamplifier with 6.1 or 7.1
processing — the main function of these extra jacks on a
home theater receiver is to keep you ready for future
gear and future surround formats.
5-way
binding post speaker terminals
5-way binding posts are a
versatile type of terminal used for amplified,
speaker-level signals, usually found on higher-quality
speakers and receivers. This kind of terminal accepts 5
kinds of speaker wire connections: bare speaker wire,
pin connectors, spade connectors, banana plugs, and dual
banana plugs. Some binding post connectors aren't
considered "5-way," because they don't accommodate every
one of these connection types.
Each speaker (or
each output channel on a receiver) uses a pair of
binding posts for a single connection: one for the
positive speaker lead (usually red), and one for the
negative lead (usually black).
75-ohm
coaxial jack
Sometimes called an "RF
input," this kind of jack is commonly used for hooking
up antennas, cable boxes, VCRs, TVs, etc. A 75-ohm
coaxial cable can carry video and stereo audio
information simultaneously. RF cable connectors (often
called "F-type" connectors) either screw onto the 75-ohm
jack, or just push on to connect.
There are
different types of coaxial cable. Standard coaxial cable
is stamped "RG-59"; higher-quality "RG-6" cable features
better shielding, and exhibits less high-frequency loss
over longer runs. (For connecting DBS satellite systems,
it's essential to use RG-6 cable to correctly pass the
entirety of the digital signal.)
Analog
audio minijacks
Most portable CD players,
MD recorders, and computer sound cards use minijacks for
their analog audio inputs and outputs. Portable players
usually output sound via a single headphone minijack.
Portable recorders usually add 2 additional minijacks: a
line input and a microphone input.
PC sound
cards typically have at least 1 minijack line output;
some also have a separate headphone minijack output.
Like portable recorders, most sound cards also feature
minijacks for line input and mic input (these permit you
to record sound directly to your hard disk drive).
Most minijack connections are stereo;
that is, they pass both a left and a right audio
channel. However, some minijack connections (such as
microphone inputs) pass just a single mono audio
channel.
Coaxial
digital jack
This type of jack is used
for the digital audio inputs and/or outputs on A/V
components such as receivers, CD players, DVD players,
and more. Coaxial digital jacks are also sometimes found
on higher-end PC soundcards for digital audio input and
output.
Coaxial digital inputs and outputs use
standard RCA-type jacks (so coaxial
digital cables are terminated with standard RCA
connectors). But the cable itself is specially designed
to handle the much wider frequency bandwidth of digital
signals.
Component
video jacks
This 3-cable connection
allows the chrominance (color) and luminance
(brightness) portions of a video signal to be processed
separately. S-video works similarly, but
component video improves color accuracy further by
splitting the chrominance signal into two portions.
Component video connections are found on most
DVD players and HDTV tuners, and on a growing number of
TVs and A/V receivers. However, this type of connection
can vary in bandwidth from unit to unit. To pass
progressive-scan DVD signals without noticeable
softening of the picture, a component video connection
should have bandwidth of 12 MHz or higher; passing HDTV
signals without softening requires bandwidth of 30MHz or
higher. If you are only slightly shy of the required
bandwidth for the signal you're viewing and your TV is
36" or less, the picture softening may be extremely
subtle, or even unnoticeable.
Composite
video jack
A composite video input or
output uses a single standard RCA-style jack to pass
video signals. This type of connection combines
chrominance and luminance information, sending it along
a single cable. Though capable of delivering a
high-quality picture, composite video is not as accurate
as either S-video or component video, both
of which provide separate paths for chrominance and
luminance.
Commonly found on A/V components like
DVD players, VCRs, TVs, DBS systems, etc., composite
video jacks are often grouped with corresponding stereo
audio jacks (the composite video jack is usually
yellow). Though they use standard RCA-type connectors,
composite video cables are specially designed to
maximize video signal transfer.
DVI
(Digital Visual Interface) jack
DVI is a multi-pin
connection used for carrying high-definition video
signals, found on HDTV tuners and HDTV-ready
televisions, as well as some computer displays. The DVI
standard for HDTV incorporates a form of copy protection
known as HDCP (High-bandwidth Digital Content
Protection).
There are actually two types of DVI
connections. DVI-D, which is the type of DVI
connection found on most home video gear, carries
digital-only signals. DVI-I, used with some
computer video cards, is capable of passing both digital
and analog video signals. Some TVs feature DVI-I inputs
for greater hookup flexibility.
Ethernet
card
The most popular form of
Network Interface Card (NIC) available, Ethernet cards
allow PCs to interface with one another over home
networks and broadband Internet connections. The very
popular 10/100 Base-T Ethernet card — now a standard
inclusion on many new PCs — allows transmission speeds
of either 10 Mbps (megabits per second) or 100 Mbps,
automatically self-adjusting to the proper speed for the
type of connection being made. With this flexibility,
Ethernet cards are capable of a particularly wide
variety of connection options.
Game/MIDI
port
MIDI stands for Musical
Instruments Digital Interface. The MIDI protocol lets
PCs and electronic musical instruments (like digital
keyboards and sequencers) share performance data with
each other. Today, another very popular use for this
port type is as a joystick interface for many PC games.
(Also called game ports.)
Musical instruments
use a different type of jack for MIDI connections. To
connect a MIDI-capable instrument and PC, you'll need a
special adapter cable.
i.LINK
port
i.LINK, also known as IEEE
1394 or FireWire™, is an extremely fast (up to 400
megabits per second), two-way digital connection used
between computers and peripherals like digital
camcorders. It is used in digital camcorders because it
is one of the few connections capable of quickly
transferring full-motion video. Most consumer video
equipment uses 4-pin i.LINK ports and connectors, but
some peripherals employ a 6-pin i.LINK configuration.
Mini-optical
jack
This type of jack is
commonly used for the digital audio input and output of
portable audio devices. A mini-optical jack is the same
shape and size as a standard analog audio minijack. This
allows portable MiniDisc recorders to use a single input
jack that accepts both mini-optical connectors and
standard analog audio minijacks. The MD portable detects
whether you're making a digital or an analog connection
based on the type of cable you're using, and
automatically selects the appropriate recording mode.
Optical
digital jack (Toslink)
This type of jack is
commonly used for the digital audio inputs and outputs
on home A/V components such as receivers, CD players,
full-sized MD recording decks, DVD players, and more.
Also, some higher-end PC sound cards offer digital input
and output using Toslink jacks.
Toslink jacks
and connectors usually come with protective caps which
need to be removed before connections are made.
Parallel
port
The parallel port is one
of the oldest PC-peripheral connection technologies
still in existence. As such, it's significantly slower
than many of the connection types that have followed in
its wake — particularly USB and i.LINK — and its
popularity has declined correspondingly. The parallel
port most often takes a 25-pin connector, and in years
past was very commonly used to connect printers and
other external devices to PCs. Today, many new PCs (but
almost no peripherals) offer parallel ports, although
adapters are available for people wishing to connect a
newer device to an older computer via a parallel port.
PCI
slot
PCI is an acronym for
Peripheral Component Interconnect. As the name implies,
this is a slot that allows you to connect various
peripheral devices to your PC, such as ethernet cards,
sound cards, and TV tuner cards. The slots themselves
can only be accessed by opening your computer's case, so
they're not designed to support the frequent
peripheral-swapping you can do with connection
technologies like USB and i.LINK.
Phono
(turntable) input
When a turntable plays a
vinyl record, it produces an audio signal that's
considerably different from the standard line-level
signal output by CD players, tape decks, and other
components. Not only is the phono signal much lower in
voltage, but the process of vinyl mastering involves
applying a special equalization curve that cuts low
frequencies and boosts highs. (This prevents the
"overcutting" of grooves, and minimizes noise.)
Many receivers feature a specialized phono input
intended for turntables only. The signal coming
from this input is sent to a dedicated preamp circuit
which applies inverse equalization and boosts the signal
up to the standard line level — resulting in proper
sound from your turntable. (Keep in mind that feeding an
ordinary line-level signal into your receiver's phono
input will probably result in horrific distortion, and
could actually damage your amplifier and speakers!)
Receivers with a phono input also feature a
ground screw for connecting your turntable's ground
wire. (Neglecting this connection can result in an
audible hum from your system.) If your receiver or
preamplifier doesn't have a specialized phono input, you
can use an in-line phono
preamp, which allows you to connect your turntable
any regular line-level input.
PS/2
keyboard port
The keyboard port used by
virtually all Windows®-based PCs, employing a 6-pin
configuration. Many CD mega changers with memory for
disc and song titles now feature their own PS/2 jack —
this allows you to plug in a keyboard for speedy naming
of your CDs. Additionally, some PC-friendly peripherals
Y-jack into your PS/2 port as a source of power.
RGB
(D-sub 15-pin) jack
Found on some HDTV-ready
TVs and HDTV tuner boxes, RGB connections are used for
transferring video signals, including high-definition
content. As implied by its name, RGB sends the red,
green, and blue components of the video signal along
separate paths.
Though RGB connections can take
a number of forms, one that's increasingly common on TVs
and set-top boxes is the D-sub 15-pin jack. If
you own a computer, D-sub 15-pin connections may look
familiar — they're the same ones found on standard
VGA-type computer monitors. RGB connections pass video
signals in the analog domain.
RJ-11
and RJ-14 phone/modem jacks
PC modems, DBS receivers,
hard disk video recorders, and other kinds of A/V gear
use these jacks for sending and receiving information
via a telephone line. Usually computer modems feature a
second phone jack — this allows you to plug in a
telephone that will be operational whenever the modem is
not in use.
RJ-11 jacks and connectors
allow for the transmission of a single phone line;
RJ-14 connections can carry two separate phone
lines simultaneously. The connectors for one type will
fit into the jacks of the other, but if you plug an
RJ-14 cable into an RJ-11 jack, you'll lose the ability
to access the second line from the computer and/or phone
thus connected.
Serial
(RS-232C) port
A serial port, or RS-232C
port, is an interface that provides low-speed
communication between your PC and attached devices (such
as digital cameras, printers, and more). Because it is
so slow in comparison to newer connections (like USB or i.LINK), fewer and fewer peripherals offer serial
connections, and new PCs tend to provide only one serial
port, if any. Serial ports most frequently take a 9-pin
connector, although a number of older peripherals employ
25-pin serial ports.
Speaker
wire (no connector)
Speaker wire consists of
two leads, typically encased and bundled in plastic
insulation — one for the positive signal, and one for
the negative. Usually, speaker wire is marked (+) and
(-) to help you distinguish between the two.
Though it's not an ideal long-term installation
method, you can connect your speakers and receiver using
just the bare, stripped ends of your speaker wire.
Drawbacks to this approach include:
- Stray wire strands, if not properly twisted, could
make contact with the cable's other lead, and cause a
potentially harmful short circuit.
- Bare wire ends corrode, since they're made of
copper. Most speaker wire connectors, on the other
hand are usually coated with a corrosion-free
material, such as gold.
Speaker
wire connectors
All kinds of speaker wire
connectors are designed to accomplish the same job: to
make solid electrical contact between your speaker wire
and your gear. By using speaker wire connectors, you
reduce the risk of a short circuit caused by frayed wire
strands. And since speaker wire connectors usually have
corrosion-free contacts, they help maintain optimum
connection over the long term.
There are 4 main
kinds of speaker wire connectors:
- Pins. Pin connectors may either by straight
or angled. They work with spring clip speaker
terminals, as well as with binding posts.
- Spades. Spade connectors feature a forked
piece of metal, designed to hug the collar of a 5-way
binding post terminal. The spade is then secured by
tightening the binding post's cap. Spade connectors
give you very secure contact.
- Banana plugs. If you have binding post
terminals on your speakers and/or receiver, banana
plugs are a great choice. The flexible metal collar of
a banana plug is slightly wider than the center hole
of a binding post. It compresses to fit when you plug
it in, resulting in a very solid connection. Banana
plugs are extremely quick and easy to hook up.
- Double-banana plugs. The same as banana
plugs, except the positive and negative banana
connectors are both fixed in a molded housing that
spaces them 3/4" apart. (These are even quicker and
easier to connect than regular, single banana plugs —
as long as the terminals on your speakers and/or
receiver are true 5-way binding posts with the proper
spacing.)
Spring
clip speaker terminals
Spring clip terminals are
a type of connection used for amplified, speaker-level
signals, usually found on lower-priced speakers and
lower- to medium-priced receivers. Spring clips accept
bare speaker wire, as well as pin-type speaker wire
connectors. To make the connection, just push the
spring-loaded lever, insert the wire (or connector), and
release. Spring clips are sometimes also referred to as
"push terminals."
Each speaker (or each output
channel on a receiver) uses a pair of spring clips for a
single connection: a red one for the positive speaker
lead, and a black one for the negative lead.
Stereo
RCA jacks
RCA connections are the
standard means of passing analog line-level (or
"preamp-level") audio signals between components. RCA
jacks are commonly found on most types of A/V gear:
receivers, CD players, turntables, MiniDisc recorders,
cassette decks, VCRs, DVD players, and more.
The
audio inputs and A/V inputs found on
receivers are RCA connections (though some A/V inputs
may also include a different type of jack — such as
S-video or component video — for the "video" portion of
the signal).
Usually, RCA jacks, connectors and
cables are grouped in stereo pairs, with one
connection for the left audio channel and one for the
right. However, some components (such as many powered
subwoofers) use a single mono RCA jack for audio
input and/or output.
(Note that a turntable's
RCA jacks output a signal that's significantly different
from standard line-level signals; hookup requires a
specially designed phono input or an in-line phono preamp.)
S-video
jack
Found on DVD players, DBS
receivers, Super VHS VCRs, TVs, and other kinds of A/V
gear, S-video inputs and outputs use a round, 4-pin jack
to pass video signals. The "S" in S-video stands for
"separate": S-video connections transmit the chrominance
(color) and luminance (brightness) portions of a video
signal along different paths, allowing them to be
processed separately.
S-video provides a sharper
picture than composite video. However, component video connections yield even better
performance than S-video by further dividing the
chrominance portion of the video signal.
USB
audio adapter
A kit that allows you to
output PC audio signals from a primary USB port on your computer to an external
component, such as an MD recorder or A/V receiver.
Unlike the analog output of your PC's line-out jack,
audio signals exported via USB are still in pristine
digital form when they leave your PC. This offers you
two big benefits on the sound quality front. First, you
skip the low-quality digital-to-analog (D/A) conversion
employed by many PC sound cards. Second, no analog audio
routing or processing takes place within your computer's
case, which is a hotbed of electrical activity that can
easily muddy the clarity of audio signals.
If
you use a USB-to-digital audio adapter, this signal is
then passed on directly to the digital input of the
connected component. If you're using a USB-to-analog
adapter, the signal is converted to analog by a
high-quality inline D/A converter before being passed on
to the audio component's analog input. You can also use
an analog USB adapter to connect your powered speakers
for better sound quality than you'd get by plugging them
into your PC card's line-out minijack.
USB
port
USB (Universal Serial Bus)
is a "plug and play" interface between a computer and
peripherals (like audio players, digital cameras,
joysticks, keyboards, and printers), which lets you plug
in a device without adding an adapter card or even
restarting your PC.
Its speed makes it ideal for
music and digital still transfer. USB 1.1, the familiar
USB standard of the last several years, supports a data
transfer speed of 12 Mbps (megabits per second) —
significantly faster than a serial connection. Though USB 1.1 can't compete
with i.LINK (which maxes out at 400 Mbps), the
up-and-coming USB 2.0 standard is even faster — 480
Mbps!
Today, most new computers (both
IBM-compatible PCs and Macs) and many peripheral devices
are equipped with USB; for example, USB support is
integrated into Windows® 98, 98SE, 2000, 2000SE, ME and
Windows XP, as well as Mac OS 8.6 and up.
USB
ports are expandable with the addition of hubs, which
allow you to connect several peripherals simultaneously
through a single USB port. Many newer PCs offer multiple
USB ports, often placing one or more on the front of the
case for easy access. Note however, that usually only
one port is designated the primary USB port, and some
peripherals will not work when plugged into secondary
ports.
There are three types of USB connectors.
The USB Type A connector plugs into the USB port
on your computer. The USB Type B connector plugs
into a peripheral device (such as a monitor or printer).
Some smaller devices like cameras and USB audio adapters
feature a smaller version of the Type B jack, known as
mini (Type B). These devices typically include a
Type A-to-mini-USB (Type B) cable.
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