Cable switches are used to connect multiple signal inputs (computers, DVD players, video game consoles, etc.) to a single output (televisions, computer monitors, etc.). Switches all work on the same general principle and most are purely mechanical. A switch only goes from multiple inputs to one output; if you need to go from one input to multiple outputs, you will need a splitter instead.
Switches are used when you have a screen, such as a TV or computer monitor, that does not have enough ports. For example, say you have a TV with one HDMI port but you want to connect a DVD player, a laptop, and a video game console. One option would be to constantly reach behind the TV and switch the cables, but that gets old fast. The simpler solution would be using a switch that connects all three devices to the TV and lets you change between them at the push of a button.
Most switches are mechanical and do not require a power cable to work. The inside of a switch works similar to switching the rails on train tracks. Say you have a 2-way switch, so the signal can come in from Input A or Input B. If the switch is set to Input A and you press the button to change it to Input B, parts inside the switch move from A to B to change the connection. This is why switches can only use one input at a time. If a switch was built to use multiple signals at once, the signals would interfere with each other and none of them would work.
Coax Cable Switches
Coax cable switches are usually used to switch between an antenna and another connection like cable or satellite. Each coax switch uses F-type connections, the same type of screw-on connection used on the back of televisions.
Coax switches can be rated for different Radio Frequency (RF) ratings, measured in MegaHertz (MHz). Most coax switches will fall into the 5-900 MHz range that is used for antenna and cable television signals. Satellite signals run between 950-2350 MHz, so users connecting a switch to a satellite must make sure they have a switch rated for that RF range.
HDMI switches are commonly used on televisions that do not have enough HDMI ports. HDMI is the new standard for audio/video connections, but some TVs only come with one or two HDMI ports. Between all the different devices that use HDMI to connect to a TV (DVD and Blu-ray players, video game consoles, laptops, tablets, smartphones, camcorders, etc.), sometimes there are just not enough ports to go around.
Many new TVs are HDMI-only, with adapters/converters being needed to use older devices that connect with other types of cables to HDMI. While this is certainly handy, it makes needing more HDMI ports even more likely and that is where HDMI switches come in.
Unlike most other switches, HDMI switches are not purely mechanical. HDMI cables transmit small amounts of power alongside their audio/video signals, but sometimes they need a little extra boost. Most HDMI switches come with a power adapter for connecting to a wall outlet when that is the case.
HDMI switches are also able to equip IR (infrared) sensors, giving users the option to use a remote with the switch instead of getting up and hitting a button on the switch itself. The IR extension uses more power than an HDMI switch would need otherwise, so the wall outlet adapter is usually necessary when the IR equipment is connected.
Network (Ethernet) Switches
Network switches are unique in that they work more like a splitter than like other types of switches. Ethernet signals cannot be split, which is where network switches come into play. A network switch allows users to connect multiple devices through a single ethernet port. Technically, a network switch only sends one signal at a time like any other switch. However, the signals are sent so quickly that multiple signals are transmitted back and forth in less than a second. This makes it seem like multiple devices are working simultaneously because it goes so fast.
USB switches allow one device to be connected to multiple computers using USB. For example, if more than one computer needed to be connected to a single printer in a small office without everything being networked together. USB switches can even share smaller devices like a mouse or keyboard for a set-up like two computers at a single workstation being used by different people on separate shifts. Most USB switches use USB B cables, the same type of USB cable typically used to connect a computer to a printer.
RCA is the old standard for home audio/video and is found on devices like VCRs and older versions of modern equipment like DVD players, camcorders, and video game consoles. RCA switches are plug-and-play, making them very simple to use. They are a bit easier to use than other switches since RCA is a simpler type of cable.
VGA switches are simplistic and typically used to share one computer with two different monitors or two different computers with one monitor. This is useful for setting up two or more separate desks or workstations using a single computer or a single monitor. Only one desk/workstation would be usable at a time, but it does allow separate working spaces without having to purchase multiple computers or multiple monitors.