Every wonder what the difference was between CAT5, CAT6, and CAT7 wiring? How about the difference between UTP, ScTP, and STP cabling? Do you need a CCTV? The answer to these and many other questions that we commonly encounter are answered here on this Frequently Asked Questions section of our web site. Use the search engine to narrow your search through our site. Contact us if you need more information or can’t find the information you are looking for. We will be happy to provide you with an answer.
What is the difference between UTP and STP cables?
UTP cable relies solely on the cancellation effect, produced by the twisted wire pairs, to limit signal degradation caused by EMI. To further reduce crosstalk between the pairs in UTP cable the number of twists in the wire pairs varies. UTP uses 100 ohm of resistance: whereas, STP generally has 150 ohms of resistance. ScTP, unlike UTP cabling, has a metallic braid or foil that adds additional protection against EMI.
What is UTP cabling?
Unshielded Twisted Pair (UTP) is a cable with multiple pairs of twisted insulated copper conductors bound in a single sheath. The wire pairs are twisted because it helps reduce crosstalk and noise susceptibility. UTP cabling most commonly includes 4 pairs of wires enclosed in a common sheath. 10Base-T, 100Base-TX, and 100Base-T2 use only 2 of the twisted pair, while 100Base-T4 and 1000 Base-T require all 4 twisted pairs. UTP most often refers to the 100 ohm Category 3, 4, and 5 cable types specified in the TIA/EIA 568-A standard:
- Category 3, (Cat 3) cable supports transmission at frequencies up to 16 MHz.
- Category 4, (Cat 4) cable supports transmission at frequencies up to 20 MHz.
- Category 5, (Cat 5) cable supports transmission at frequencies up to 100 MHz.
- Category 5e, (Cat 5e, Enhanced Cat 5, Cat 5+) is a new cable standard that will specify transmission performance that exceeds Cat 5. Cat 5e has improved specifications for NEXT, PSELFEXT, and Attenuation. Like Cat 5, it consists of unshielded twisted pair with 100 ohm impedance and electrical characteristics supporting transmission at frequencies up to 100 MHz.
- Category 6, (Cat 6) is a proposed standard that aims to support transmission at frequencies up to 250 MHz over 100 ohm twisted pair.
- Category 7, (Cat 7) is also a proposed standard that aims to support transmission at frequencies up to 600 MHz over 100 ohm twisted pair.
What is STP cabling?
Shielded Twisted Pair (STP) is the 150 ohm twisted pair cabling defined by the IBM Cabling System Specifications for use with Token-Ring networks. The twisted pairs in 150ohm STP are individually wrapped in a foil shield and enclosed in an overall outer braided wire shield. This shielding is designed to minimize EMI radiation and susceptibility to crosstalk. The various versions of 150 ohm cable are identified by a IBM "Type" number; Types, 1, 2, 6,8, and 9 for support of Token-Ring frequencies up to 16Mhz and Types 1A, 2A, 6A, and 9A for support of FDDI frequencies up to 100 Mhz.
What is ScTP cabling?
ScTP (Screened Twisted Pair) cable is a four pair UTP with a single foil or braided screen surrounding all four pairs in order to minimize EMI radiation or susceptibility. ScTP is sometimes called Foil Twisted Pair (FTP). ScTP can be thought of as a shielded version of the category 3, 4, and 7 UTP cables.
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