Telephone cords are one of the more basic types of cables. Phone cables have remained mostly the same over the years with a few small changes here and there. There is a little terminology to know that will tell you a bit more about your phone lines, such as how they are wired and what type of plastic connector is on the end of the cable.

 

Key Takeaways

  • Telephone cables are designed primarily for telephone and voice connections.
  • RJ11-style connectors are commonly associated with traditional telephone applications.
  • Telephone cables are available in different conductor and pair configurations.
  • Always verify the connector, wiring configuration, conductor count, and cable length before purchasing.
  • Telephone and Ethernet cables are not automatically interchangeable.
  • A similar-looking modular connector does not guarantee compatibility.
  • Choose cable construction according to the installation environment.
  • Proper cable routing and management can make telephone systems easier to maintain.
  • Test telephone cables after installation or repair to identify wiring and continuity problems.
  • Damaged connectors can often be replaced when the cable itself remains in good condition.
  • For severely damaged cables, complete replacement may be more reliable than repeated repairs.
  • Selecting the right telephone cable requires matching the cable's connector and wiring configuration to the equipment and application.

 

Phone cords come in two varieties, flat cords used to connect phones to the wall and coiled cords used for handset receivers. Flat cords will use either an RJ11 or RJ12 connector. These two connectors are the same size and look the same on the outside. On the inside, RJ11 will have four metal contacts for the internal wires inside the cable while RJ12 cable has six contacts. Since they are the same size, RJ12 is backwards compatible with RJ11. However, since RJ11 is the older of the two it is not compatible with RJ12.

The next distinction is whether your flat cord is straight or reverse. Straight cables are used to send data, like a fax machine, while reverse cables are used for voice, like a telephone. On a straight cable, the telephone wire will connect to the same metal pins on either side of the cable. Pin 1 to pin 1, pin 2 to pin 2, etc. On a reverse cable, the opposite is true. For RJ12, a reverse cable would go pin 1 to pin 6, pin 2 to pin 5, etc.

Round versions of the flat cord also exist but are usually used for something other than a phone. Typically, they are equipped with extra features that make them larger than the average flat cable, such as something built for outdoor use or a cable designed to connect an Internet modem to a wall jack.

 

Phone cord cable straight reverse pinout wiring scheme diagram

 

A straight pinout (left) vs. a reverse pinout (right)

Coiled phones cords are made to connect handset receivers to the base of the phone. The connectors on these are smaller than the ones on a flat line cord, using either an RJ9 or RJ22 connector. RJ9 and RJ22 are two different names for the same thing. Being smaller than RJ11/RJ12, these connectors only have room for four metal contacts instead of six.

The size of a coiled phone cord can be somewhat confusing. Most companies will list the size the cord would be if it was completely uncoiled. On average, 6 feet of uncoiled cord equals about 1 foot coiled. So if you order a phone cord labeled “6 feet” for length, it will be 1 foot coiled up all the way and stretch to about 3-4 feet. Coiled phone cords are generally made in four sizes: 6 feet (1 foot coiled; small), 12 feet (2 feet coiled; medium), 25 feet (4 feet coiled; long), and 50 feet (8 feet coiled; extra-long).

 

 

Exactly how far a cord will stretch varies from cable to cable. The strain from extended stretching can potentially break the cable or send your phone crashing to the floor. Long, worn out cords are also get tangled easier but this can be remedied by using a cord detangler.

 

 

 

Tips for Choosing Telephone Cables

 

1. Identify the Application

First, determine what the telephone cable will be used for. Traditional telephone cables can be used for telephone handsets, wall-jack connections, telecommunications equipment, and other compatible voice applications.

2. Check the Connector Type

Check the connector required by the telephone or equipment.

RJ11-style connectors are commonly associated with telephone connections, but connector configurations can vary depending on the application.

3. Check the Number of Conductors

Telephone cables are available with different conductor and pair configurations.

Choose a cable that provides the conductors required by your telephone system or equipment.

4. Verify the Wiring Configuration

Before replacing an existing telephone cable, check how the conductors are arranged.

Do not assume that all telephone cables use the same wiring configuration or colour sequence.

5. Choose the Correct Cable Length

Select a cable long enough to comfortably connect the equipment without excessive slack.

For permanent installations, plan the complete cable route before choosing the cable length.

 

FAQs – Frequently asked questions

 

What is a telephone cable?

A telephone cable is used to connect telephone equipment to telephone lines, wall jacks, or compatible telecommunications equipment.

What are telephone cables used for?

Telephone cables are commonly used for telephone handsets, wall-jack connections, voice systems, and telecommunications applications.

What are the different types of telephone cables?

Telephone cables can differ by conductor count, number of pairs, connector configuration, cable shape, length, and intended application.

How many wires are in a telephone cable?

The number of wires can vary depending on the cable and application. Some telephone cables contain a single pair, while others contain multiple pairs.