There are many different ways to connect copper cable to your networking equipment. In this video, you’ll learn about RJ11, RJ45, BNC, DB-9/DB-25, and F connectors.
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If you’re connecting up a traditional phone line or you’re using a modem connection over a traditional phone line, then you’re probably using an RJ11 connector. This is what we call a six position, two conductor cable or a 6P2C connector. You can see there are six different types of positions that can be on these cables. But if you look into a modem, you’ll see that only two conductors are in use.
If this is an RJ14 cable, that means that it may be using dual lines and it may fill in two more of these wires to be a six position, four conductor cable. If you’re connecting a telephone or a modem to a traditional public switch telephone network, a PSTN, or the plain old telephone system or POTS, then you’re probably very familiar with the RJ11 connector.
We use a modular connector that’s a little bit larger for Ethernet. It is an RJ45 connector. The RJ stands for registered jack. This is an eight position, eight conductor cable, and we do use all eight of those conductors for our gigabit Ethernet. You can see all eight of those conductors are in use, and if you’re connecting an Ethernet network over copper then you’re using an RJ45 connector.
A bayonet connector is one that you push in and twist to be able to lock into place. And a common bayonet connector used for networking is the BNC connector. It stands for Bayonet Neill-Concelman. It’s created by Paul Neill at Bell Labs and Carl Concelman at Amphenol. And we commonly see this used on WAN connections like DS3.
We’ll bring in the coax cable and connect it up through that bayonet connection. These are coax cables, so they can be relatively rigid and bulky to work with. And if you’re plugging in a lot of DS3 networks, then you’ll have a lot of BNC connectors on your patch panel.
Another common copper connector is the DB-9 connector. The D in DB-9 stands for D-subminiature or D-sub. Specifies this type of connector that looks like a D. There are different sizes from DA through DE. You’ll see the DB-25 listed, and the DE-9 is listed here at the bottom.
The DB-25 was one of the most popular serial connector types early on in computing. And when the nine-pin version of this was released, we started calling it the DB-9 even though technically it’s a DE-9. These are commonly used for what we call an RS-232 serial connection. And early on in our computers, we used these for almost everything, modems, printers, mice, networks, and anything else that we needed to be able to send some type of signal over.
These days, we don’t commonly see the 25-pin connection in use. It’s most often the nine-pin connector, and it’s often used as a console connection for a router, a switch, or some other type of infrastructure device. Here’s a back of an older motherboard that has a DB-25 connector used for printing. There’s a DB-9 serial connection, and that’s what we would connect our cable to so that we can access a router or switch at the command line.
If you’ve connected cable television or cable Internet modem, you’ve probably brought it in through coax with this F-connector at the end of the cable. It’s usually brought in on something like an RG-6 cable for this coax connection, and it uses this threaded connector. Once you twist it on to the connector, it’s not coming off of that connection unless you completely untwist this F-connector.