What are IP Phone Jacks, and How Are They Wired?

Phone jacks, come in two different flavors RJ45 and POTS, but RJ45 is the style used for IP phones and is most commonly seen in networking, specifically in communication. These are cables and services capable of sharing information across their length, allowing effective communication no matter the distance.

To start it off, RJ45 is a cable that is used to connect devices to the Ethernet, which is responsible and capable of transmitting communication across locations far away. The same goes with POTS, which would be the original telephone system.

What is an RJ45 Cable

The “RJ” in RJ45 means Registered Jack, with the number 45 coming from its number of interface standards. This RJ45 cable connects the computer to the switch—which would be responsible for letting the devices communicate with one another—and, unlike other cables, it is an unshielded twisted pair.

An unshielded twisted pair of cable is a cable without the extra layer of metal coating it. If you took a closer look at an RJ45 cable, you would see eight wires in it, which are all placed into four pairs. Despite being in pairs, however, they are still twisted individually and in a specific number of twists per foot.

How Do You Wire an RJ45 Cable?

Step 1: Straighten the Wire

Straighten the CAT5 or CAT6 Cable

This is an important step, terminating the cable requires it to be straight

Step 2: Strip the Cable

Strip the Cable

Strip the blue sheath back about 3/4″ of an inch exposing the small wires inside

Step 3: Separate the Pairs

Seperate the Pairs

The wires have to be put into the RJ45 jack in exactly the right order, before that happens its easiest to separate the pairs.

Step 4: Put On the Protective Boot

This boot helps to keep the connector from breaking

Step 5: Re-Order the wires

Reorder the wires

It’s important that you order the wires exactly the same way as pictured


Step 6: Straighten the wires

Straighten The Wires

Step 7: Slide on the Jack

Step 8: Crimp the connector

Step 9: Cable Finished!!

Step 10: Test Your Cable

There are very inexpensive cable testers available these days. I strongly recommend testing the cable before using.

There are also shielded twisted pair cables, and they are still functional, but what makes an RJ45 unshielded twisted pair cable more beneficial to use is that it would not take as much space. If I opted to run a thousand cables across from my primary data center, shielded twisted pairs would take a lot more space, and I would find it harder to work with it since it does not bend as much.

Aside from that, unshielded twisted pair cables are cheaper and are also dispensable. The installation process would be easy as there aren’t any unique or professional steps needed to be done. Since UTP cables are also smaller, they could be easily compressed and fit into tight spaces.

Is RJ45 the same as the Ethernet?

You might have been asking that because people often use the term RJ45 and Ethernet cables interchangeably. In reality, RJ45 is the type of termination of the twisted pair cable, while an Ethernet Cable is a piece of cable with two ends, each terminated with an RJ45 style end.

While we’re on the subject of definitions, another essential term is “Ethernet,” which is a way of connecting computers or devices in a local area network, or otherwise called “LAN.”

How do I connect RJ45 cables?

Hold the RJ45 cable in a way that its pin is looking away from you with the plug-clip facing down before inserting its flattened, organized wires into the connector. You should carefully push through until you see the wire ends appear from the pins.

What are a POTS, and How is It Wired?

On the other hand, POTS stands for “Plain Old Telephone System,” and it is responsible for receiving and giving calls—in simpler terms, it is the landline on your desk, the one you would use in reaching out to people far from you.

Unlike the aforementioned, POTS are neither shielded nor unshielded. Instead, it is a copper twisted pair. There are still eight wires twisted individually and with a specific number of twists, as well, before being put into four pairs.

What’s different is that a copper twisted pair uses a typical copper wire that is responsible for connecting your home or business to the telephone company. The copper wire pairs in the cable are insulated so that the possibility of crosstalk —which is the electrical noise made by pairs near each other— is avoided.

How do POTS lines work?

The process is simple, dating back to the 1970s. It is delivered through copper wires and to the central office of your neighborhood. These central offices would be the ones to transmit your calls locally, nationally, or even internationally.

How much would a POTS line cost?

It will vary on the service you are signing up for, but most services would charge you around $20 to $60 per month. There are also ways. However, that offers a reduction on your monthly POTS line charges and can help you save more money.

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