Audio/video
devices use a variety of different interfaces. One similarity that most
A/V connector types share is their ease of pluggability. Manufacturers
of consumer electronics prefer to use simple interfaces that average
users can plug and unplug without having to tighten thumbscrews, or
release tabs or latches. This preference can prove challenging to
manufacturers who must balance convenience with performance.
1/4-inch
The
1/4-inch connector is commonly called a phone connector because it was
used for years by telephone operators to patch telephone connections
together. It has a tip/ring/sleeve design, like the 3.5mm connector,
but it is larger in length and diameter. The 1/4-inch connectors may
have only a tip and sleeve, or a tip, ring and sleeve (TRS). A TRS
connection is used for balanced audio lines, or depending upon the
equipment, for stereo sound. The 1/4-inch connectors are very common on
musical instruments (especially guitars), and other staging devices
such as effects pedals, mixing consoles, speakers, and amplifiers. Cables
3.5mm
The
3.5mm connector is commonly called a 1/8-inch connector or a mini-plug.
It is a small, thin metal plug that can be used to carry one, two, or
even three signals. The tip of the plug is separated from the sleeve of
the connector by a concentric band of insulating material. For stereo
or audio/video versions of the plug, there may be one or two additional
metal bands, called rings, placed between the tip and the sleeve. 3.5mm
connectors are commonly used for computers and portable devices. A
computer’s sound card uses these connectors for speakers,
line-in/line-out connections, and also for microphones. Portable
devices use the 3.5mm interface as a line-out connection for headphones
or for connection to an auxiliary input on an amplifier. The
“three-pole” version of the 3.5mm plug is often used on camcorders. This plug has a tip and two rings, which can carry video as well as right/left stereo audio. Cables
BNC
BNC
connectors are round plugs with a bayonet-style locking system, used on
coaxial cables. BNC plugs have good impedance characteristics, and
their locking mechanism keeps them securely in place once connected.
Because they are more expensive and harder to connect than RCA plugs,
they are often used for higher-end and/or professional audio/video
equipment. They are very common in CCTV and surveillance camera
applications. There are many popular theories explaining the acronym
“BNC”, but the most likely is “Bayonet-Neill-Concelman”, which refers
to the two gentlemen that developed it years ago (Paul Neill from Bell
Labs, and Carl Concelman from Amphenol). Cables
DVI-D Dual-link
This
connector contains 24 pins arranged in three horizontal rows of eight
pins. To the side of this grouping of 24 pins is a wide, flat pin
called a ground bar. A dual-link interface provides two TMDS links, or
groups of data “channels” that can carry more than 10 Gbps of digital
video information. A dual-link cable is backwards-compatible with
single-link applications. DVI interfaces in the A/V world are found on
HDTVs and on HD sources such as DVRs or satellite receivers. Check
manufacturer specifications before connecting PC equipment to a DVI
interface on an A/V device. Cables
HDMI
HDMI™
stands for High Definition Multimedia Interface. This technology
carries the same video information as DVI but adds the capacity for
digital audio and control signals as well. The current version of HDMI
carries one TMDS link of digital video. Found on many
home-theater/consumer electronics devices, HDMI uses a 19-pin connector
that is held in place by friction. This connector is technically
described as a Type A HDMI connector. The Type B connector is larger
(28 pins), but it is not currently used by any devices in the
marketplace. HDMI is the interface of choice for most newer HD A/V
devices. Not only does it provide outstanding audio and video
performance, but it also supports High-bandwidth Digital Content
Protection (HDCP), a technology built into consumer electronic
equipment that prevents illicit duplication of copyrighted material. Cables
HD15
A
very common connector used mostly as a video interface for computers
and monitors. It can also be found on HD displays, and on older HD
source devices such as satellite receivers and cable boxes. The HD15 is
a High Density DB-style connector, so it can also be called an HD DB15.
Another popular name is “VGA connector”, although it is used in video
applications that support much higher resolutions (SVGA, XGA, UXGA,
etc.). An HD15 connector is the same size as a DB9 connector, but it
has three rows of 5 pins. On most HD15 male connectors, there is one
pin (pin 9) missing in the middle row. Cables
RCA
The
venerable RCA plug gets its name from the RCA Corporation, which
popularized its use on radios and phonograph players as far back as the
1940s. The RCA connector is a round plug with a central tip and a metal
ring, separated by insulating material. The tip has a smooth, domed
shape. The shape and design makes the connector extremely easy to plug
and unplug into equipment. RCA connectors are often used with coaxial
cables, where the center conductor terminates to the tip, and the
coaxial shield is in contact with the metal ring of the plug. Even
though they are used for video applications, most RCA connectors do a
poor job of maintaining a precise impedance. As such, they are rarely
used for broadcast or professional applications. The RCA plug is
sometimes referred to as a Cinch or phono connector. RCA interfaces are
very common on consumer electronics devices, for applications such as composite video, component video, and S/PDIF digital audio.
S-Video
(4-pin Mini-DIN)
The
4-pin mini-DIN connector is most often used for S-video applications.
It has 4 pins arranged in 2 rows, and a keying block to make certain
the plug cannot be inserted improperly. Even though an S-video
connector has 4 pins, it only carries two signals—luminance and
chrominance. The other 2 pins are used for signal ground connections. Cables
TOSLINK™
TOSLINK
is the name of an optical interface for digital audio signals. The
interface was developed by Toshiba, and TOSLINK is their registered
trademark. The TOSLINK (or EIAJ optical) connector is a small, round
optical conductor housed in a squarish connector body. Originally
intended for use solely with Toshiba CD players, it has been adopted by
many other manufacturers and is standard equipment on many A/V sources
and receivers. Even though TOSLINK uses fiber optic cable, it is
limited to a maximum cable length of about 5 meters, due to the low
power of the LEDs used in TOSLINK transceivers. Cables
F-type
The
F-type connector is used on coaxial cable, and is widely used for cable
TV, satellite TV, and off-air TV antenna applications. The connector is
round with the conductor of the cable itself poking through the center
of the connector body. Most F-type connectors are threaded, so that
they can be screwed into place. Some F-types don’t have threads, and
are merely pushed onto the mating connector. F-type fittings can be
terminated in a few different ways: crimp, twist-on, or compression. A
compression fitting is the preferred method, because it offers the most
secure termination, with the lowest amount of RF leakage. The origin of
the name of F-type connector is not widely known. Connectors
Banana plugs
Banana
plugs are often used to make speaker wire connections on amplifiers,
speakers, and audio wallplates. A banana plug has a metal pin that
“bows” out in the middle, resembling the shape of a banana. Banana
plugs are normally used in pairs and mate with binding posts, which are
typically found on higher-end amps and speakers. Plugs, wallplates and binding posts.
Speaker pins
Speaker
pins are also used to terminate speaker wire connections. Instead of a
wide body like a banana plug, a speaker pin has a straight, narrow
shape. These pins are used to connect to push-on speaker connections
found on many CE devices, and to 5-way binding posts. Speaker pins.
XLR
XLR
is a type of connector used for many professional audio applications.
Originally designed by ITT Cannon, the most common configuration is a
3-pin connector for “balanced” audio signals. When male and female XLR
connectors are mated, the design of the connector makes contact on pin
1 (ground) before any other pins. This prevents potential damage to the
system. A balanced audio signal offers great protection against EMI
noise, and can travel a long distance. For this reason, balanced lines
using XLR connections are often used for microphones, mixers,
amplifiers, and other pro audio devices. Cables and connectors.
