src=”” border=”0″ alt=”IEC 2013 Banner X11 B”

  title=”IEC 2013 Banner X11 B” usemap=”#map0″>

  width=980 height=43 src=”” border=”0″ alt=”2nd Blue Bar x5″

  title=”2nd Blue Bar x5″ usemap=”#map1″>

  &nbspWhat is

  Balanced & Unbalanced?Signals

  A difference in voltage between two conductors is how a receiver sees a signal,

  a potential difference. As a result, it takes two wires to make a lane for a

  signal to travel on. In fiber optic, light only needs the one glass tube to

  make its journey. As electric signals travel through conductors, the electrons

  that make the signal generate magnetic fields around their conductors. This

  ”radiation” of magnetic fields affects electrons in nearby conductors causing a

  false signal in those nearby conductors. This problem is referred to as

  ”crosstalk”. Ways to conquer crosstalk are shown below. In fiber optic, there

  is NO crosstalk, light traveling through the glass tube doesn’t get out of the

  cable and can’t effect adjacent cables because photons don’t generate magnetic

  fields like electrons do. Unbalanced RS232, Centronics

  parallel, IEEE 1284, USB, Thinnet, Audio, Video, and “single end” SCSI are just

  a few examples of Unbalanced signals. Most unbalanced signals travel Coax

  cables but a few do not. As mentioned before, it takes two wires to make a lane

  for data. In the case of the coax, one wire runs the middle while the other

  wire is the foil or braid that wraps around the outside. The two signals of an

  unbalanced connection are referred to as “signal” and “ground”. The ground is

  the zero reference while the signal has a voltage level that is above or below

  zero. This voltage level determines weather the signal is a 1 or a 0 (VGA,

  Audio & Video are Analog signals, the analog signal can have a voltage level

  anywhere between the high and low voltage levels). In RS232, the “ground” for

  all signals is shared on one conductor; this is also true of some other

  Unbalanced signals. RS232, Parallel and SCSI are more vulnerable to crosstalk

  since they have more than one signal in the same jacket and in some cases,

  sharing the same ground. Parallel and Single End SCSI suffer the worst, We

  usually don’t guarantee a parallel cable (Centronic or IEEE 1284) to work any

  longer than 40 to 50 feet. Because the signal is stronger for RS232, it can

  usually reach lengths of 300 feet, but as the data or BAUD rate is increased,

  the range is shortened. In coax cables, the “radiation” generated by the signal

  on the center wire gets absorbed by the foil or braid on the outside. Coax

  cables are the way to fight against crosstalk for Unbalanced signals. Balanced RS422, Differential SCSI,

  Ethernet 10Base-T, and Ethernet 100Base-T are just a few examples of balanced

  signals. Balanced signals have often been called “current loop” signals and

  travel on “twisted pairs” (UTP for Unshielded Twisted Pair or STP for Shielded

  Twisted Pair). The two signals in a balanced pair are like opposite charges of

  each other. What that means is if one wire has 12 volts, the other wire will

  have -12 volts. As the signal travels the pair, one wire radiates a magnetic

  field but its partner wire generates an opposite field, the two fields cancel

  out. This canceling is how balanced signals conquer crosstalk. Since Twisted

  pair wire is usually cheaper then Coax wire, balanced signals are more popular.

  Ethernet used to travel on a Coax (10Base-2 or Thinnet) but lately has been

  traveling on twisted pairs (10Base-T, 100Base-T). 100Base-T is so fast that

  the wire has to meet some specifications to carry it. The Cat 5 cable requires

  that the pairs be twisted tight enough to continue the canceling of the

  radiation. Also if the pairs are untwisted too much, the canceling won’t happen

  and you’ll get that dreaded crosstalk. Impedance The

  impedance is a value determined by the capacitance and attenuation effects that

  a wire has on the signal traveling through it. It isn’t necessary to explain

  the full details. Each signal has it’s own rating (Arcnet has 93 ohm, Audio and

  Video have 75 ohm, and Thinnet has 50 ohm). Using a cable with the wrong rating

  will distort the signal. Twisted pair cables also have an “impedance” but most

  of the time, their name usually determines the signal they carry (a Cat 5 is

  made for 100Base-T). What is the Balun? Some users

  have Unbalanced signals like Arcnet or Thinnet,

  which use coax cables, but they do not want to pull expensive coax cables. The

  Balun allows them to string twisted pair in place of coax. Baluns are used in

  pairs, one at each end of the twisted pair wire. The coax side of the Balun

  has an impedance rating and you would need to find the balun with the impedance

  rating to match the signal. The word “Balun” comes from combining the words

  ”BALanced” with “UNbalanced”. PLEASE NOTE: Putting a Balun on a Thinnet port

  doesn’t convert it to 10Base-T, a converter would be needed for that.

  Categories and Products Related

  to: What is Balanced & Unbalanced?Click Heading for Related products

  >Main Product Categories>Technical Tips >Balanced/Unbalanced

  Our online store carries items

  in the following areas;

  Mas200 Accounting

  Software | Audio & Video Accessories | Cable Assemblies Copper & Fiber | Products for computer applications | Communication, Telephone & Cell Phone

  Accessories | Cable Installation Products | Raw Cable, Connectors & Parts | Power Accessories including UPS, Surge Protectors, and

  Adapters | Tools & Testers | Wire (Raw Cable)

  website counter



  contents Copyright ? 1996-2017. All Rights


Categorized in: