Jul 03 2013

Twisted pair cables: 6 questions – 6 answers

Twisted pair cables are used in all kinds of industries. Despite other cable types, they are still used as standard cables to transmit data. But what exactly are twisted pair cables? How are they built? And where are the differences between the different types of twisted pair cables?

1. What are twisted pair cables?

The abbreviation Cat is short for Category. There are different kinds of cable categories, which we will explain later.

2. How are twisted pair cables built?

The strands of twisted pair cables consist of copper and are insulated. To prevent electromagnetic interference between the strands, two wire pairs are often shielded separately.

Most twisted pair cables consist of four twisted wire pairs. To prevent crosstalk, the wire pairs are twisted to a different degree.

3. What are the different types of shielding for twisted pair cables?

Shielding of twisted pair cablesnTwisted pair cables are shielded in different ways:

  • UTP: Unshielded Twisted Pair: the wire pairs are not shielded
  • FTP: Foiled Twisted Pair: the wire pairs are shielded with aluminium
  • STP: Shielded Twisted Pair: the wire pairs are shielded by an additional shield

The different types of shielding are often marked by the letters S, F or SF. These letters refer to supplementary materials within the cables.

  • S is short for braided shielding. The braid consists of copper and covers the wire pairs.
  • F is short for foil shielding meaning a shield consisting of metal or aluminium
  • SF refers to a combination of braid and foil

Twisted pair cables containing these supplementary materials are often used as UTP or FTP variant. Of course, these supplementary materials can also be combined.

4. What types of twisted pair cables are there?

There are different types of twisted pair cables that are divided into categories.

  • CAT 1-4: Cat1 to cat4 versions were often used for telephone installations, ISDN connections as well as primary multiplex connections. However, these types of cables are rather unsuitable for modern systems since cat5, cat6 and cat7 cables povide much better results when transmitting data.
  • CAT5: Operating frequencies of up to 100 Mhz are no challenge for cat5 cables. Therefore, these cables are usually used for installing Ethernet networks.
  • CAT6: Cat6 cables were designed for characteristics of up to 250 MHz.
  • CAT7: Cat7 cables are the cables of the future and are therefore often used for new installations. These types of cables specify a frequency range of 1 – 600 MHz. They are also suited for 10-Gigabit data transmission.

5. How are twisted pair cables classified?

The performance of a cable is often divided into classes. Cat6 cables, for example, provide a lower maximum transmission speed and frequency than cat6a cables. The classes range between A and F.

And there’s even another distinction: the one between patch cables and installation cables.

With patch cables, the conductors consist of several fine copper wires called strands. The flexible cable has a high attenuation.

Compared to patch cables, installation cables consist of one wire. That’s why installation cables are not as flexible as patch cable and have a lower attenuation.

6. How are twisted pair cables used here at G&D?

The application of twisted pair cables depends on the individual installation. For our installations, we use cat5, cat6 and cat7 cables.

How we use twisted pair cables here at G&D will be the topic of another blog post.

About the author

Bianca Schmidt

Redakteurin, Übersetzerin und Bloggerin bei der Guntermann & Drunck GmbH.

1 comment

  1. Fiber Optics Phoenix

    Thanks for sharing this great information.

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