Copper Connectors – CompTIA A+ 220-1101 – 3.1

Many of our device connectors are made over copper cables. In this video, you’ll learn about RJ11, RJ45, USB, Lightning, and other copper connector types.


If you’ve connected a traditional analog telephone or you use DSL on your network, you’ve probably used an RJ11 connector. This is referred to as a 6 position, 2 conductor connector, because although there are two wires inside of this connector, there are actually six positions where other wires could be. And in fact, you might find an RJ11 connector that has some additional wires inside of it so that there may be six positions and four conductors. This is commonly used for phone connections. And if you’re plugging in to a DSL modem, you’ll often find RJ11 is right on the modem itself.

If you’re connecting the ethernet, then you’re probably using an RJ45 connector. This looks very similar to an RJ11 connector, but this is an 8 position, 8 conductor connection. You can see all eight of these conductors are on the back of this RJ45 cable. This is commonly used for ethernet, although you may find RJ45 used for other types of connections as well. Here’s an example of an RJ11 and RJ45 connectors next to each other. This is on the back of a DSL modem. You can see the DSL connector is the smaller RJ11. And then the ethernet LAN connectors are RJ45 connectors.

If you have cable television, then you’re probably familiar with the F connector. This connector is used on a coaxial cable. And it has a threaded connection at the end to physically screw onto the connection so that it can’t easily pull off of the device. You might also use an F connector if you subscribe to an internet connection from your cable company. This is usually brought in with a standard called DOCSIS, which is Data Over Cable Service Interface Specification.

Here’s the view from the back of a cable modem. We have a male F connector connecting to the female side of the F connector. It screws onto this connection with these threads. And that keeps it in place so that it can’t easily be removed from the cable modem. If you work in a data center or a large computer room, you may have a number of punch down blocks on the back wall that’s used to connect users to the network. This is a wiring panel where the wires themselves are physically pushed or punched into the block itself. And there’s usually a connector that’s added on top of these wires or on the other side of the wiring block.

This allows you to permanently attach these wires into a wiring block, making it much easier to manage these wires in your data center. Here’s a close up of one wiring block. You can see these wires have been punched down using a punch down tool into the wiring block. You can almost see the connectors that push through the insulation of these wires to make contact with the copper that’s on the inside. This is another set of punch downs. This is on a wiring block that has this punch down on one side. And if you’re to see the other side of this block, there would be RJ45 connectors to complete the circuit.

Another set of popular connectors are used with Universal Serial Bus or USB. These are USB 1.1 and 2.0 connectors. The standard A plug is very common. The standard B plug is used for peripherals, especially printers. And we have mini B plugs and micro B plugs that are commonly used for mobile devices. The increased bandwidth in the USB 3.0 specification required that some of these connectors be changed. And you can see there are differences with the USB 3.0 standard B plug and the micro B plug that’s commonly used on those smaller connections. The USB 3.0 standard A plug is identical in size to the previous standard A plugs. But there are additional pins inside of this connector to support the higher speeds and bandwidth used by USB 3.0.

A newer style of USB connector is the USB C connector. This USB C connector is double-sided, so there’s no top or bottom. You can plug it in either orientation. It also is very small. It’s about the same size as the original USB micro B plug. And you’ll find the USB C plugs are used, not only on our peripheral devices, but they’re also used on our computers as well. This USB C plug is used for more than just serial connections. We can run different signals through a USB C cable. So you might see it used for serial connectivity, Thunderbolt devices, or DisplayPort devices.

One type of wiring connection that’s been around for a very long time is one that we refer to as a molex connector. This is a four pin power connector. It was originally created by the Molex connector company, which is why we refer to it as a molex connector. AMP makes a version of this connector called the MATE-N-LOK. And the single connector is designed to provide both 12 volt and 5 volt power for devices inside of your computer. So if you have a hard drive or optical drive that needs power or you need to power up the fans that are inside of your system, you may be able to use these molex connectors.

One way to tell if you have these molex connectors available in your computer is to look on your power supply itself. There’s probably a number of wires coming off of that power supply. And you’re looking for the molex connectors or these four pin power connectors that are already connected to that power supply. If you have an Apple device, you may be using a Lightning connector. This is an 8 pin connector that’s used to transfer data and provide power for certain models of iPhones and iPads.

This Lightning connector was introduced when micro USB was a common connector type for mobile devices. But Lightning allows us to have additional power output, especially for these larger phones and tablets. And unlike a micro USB connector, the Lightning connector doesn’t have a top or bottom. You can plug it in either orientation. If you work a lot with infrastructure devices that have console connections, then you’re probably still using a DB9 connector.

This DB9 stands for a D-subminiature connector. And the size of this connector is the B size that supports nine pins. These are commonly used to send RS232 signals from your device to, commonly, a serial port on the other side. This was originally used for modems and other serial devices. But if you’re working in a data center these days, the DB9 connector is commonly used for switches, routers, and other infrastructure devices. So on this fiber switch, you can see there is a serial console using that DB9 connection. And you would use that to be able to manage this device at the command line.