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half duplex , full duplex and other questions

Discussion in 'General Cisco Certifications' started by kobem, Jan 3, 2007.

  1. kobem

    kobem Megabyte Poster

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    i mix half and full duplex up each other. books say for "half duplex"
    ""one pair of wires with a digital signal running in both
    directions on the wire""

    i couldn't figure this out since i thought we have two wires
    here am i wrong?

    for full duplex

    "two pairs of wires .............."

    this means we have four wires? or what

    ...........................................
    and some other questions coming :

    for hubs we can't use full duplex ethernet (the book says it)
    i ask why?
    ..................................

    then how should i know the cable is half duplex or full duplex?

    .....................................

    for wan communications which cables i can use?
    can i use fiber for lan communications?
    ...........................
    you said i use router-router "utp" if they are close but think
    if both are 150 m far from each other?
     
    Certifications: CCNA
  2. Boycie
    Honorary Member

    Boycie Senior Beer Tester

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    Kobem,

    This will start you off on Duplex. I believe the other questions have been answered in previous posts.

    Regards
     
    Certifications: MCSA 2003, MCDST, A+, N+, CTT+, MCT
  3. hbroomhall

    hbroomhall Petabyte Poster Gold Member

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    Full and half duplex have nothing to do with the number wires between the ends, but everything to do with each end talking at once.

    Think of the classic radio-telephone. If you have to say 'over' at the end of your spiel, and listen to the other end until he says 'over' then that is half-duplex. If you can interrupt and the other person stops then that is full-duplex - as in a normal telephone call.

    Harry.
     
    Certifications: ECDL A+ Network+ i-Net+
    WIP: Server+
  4. hbroomhall

    hbroomhall Petabyte Poster Gold Member

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    On the hubs question. The important distinction is between hubs and switches.

    Hubs have little or no intelligence, so can't do two things (like talk and listen) at once. Switches *can* do this - so switches tend to have the capability of full-duplex.

    Harry.
     
    Certifications: ECDL A+ Network+ i-Net+
    WIP: Server+
  5. hbroomhall

    hbroomhall Petabyte Poster Gold Member

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    On how you know whether half or full duplex. Depends on the kit. Some items show this on LEDs. Some items show this on status (i.e. a software enquiry).

    Harry.
     
    Certifications: ECDL A+ Network+ i-Net+
    WIP: Server+
  6. Bluerinse
    Honorary Member

    Bluerinse Exabyte Poster

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    Nice analogy Harry 8)
     
    Certifications: C&G Electronics - MCSA (W2K) MCSE (W2K)
  7. surfer_rosa

    surfer_rosa Nibble Poster

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    I wouldn't call talking and listening at exactly the same time a normal telephone call :biggrin
     
    Certifications: None.... yet
    WIP: CCNA
  8. Baba O'Riley

    Baba O'Riley Gigabyte Poster

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    Depends, if you're a bloke it's neither and if you're a woman it's only talking.:D
     
    Certifications: A+, Network+
    WIP: 70-270
  9. surfer_rosa

    surfer_rosa Nibble Poster

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    Haha too true :biggrin
     
    Certifications: None.... yet
    WIP: CCNA
  10. Mitzs
    Honorary Member

    Mitzs Ducktape Goddess

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    Hey I heard that! And to make sure I never do again...

    [​IMG]


    Kobem, was just wondering what book you are using if you don't mind sharing with us.
     
    Certifications: Microcomputers and network specialist.
    WIP: Adobe DW, PS
  11. surfer_rosa

    surfer_rosa Nibble Poster

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    sybex, acording to another post.
     
    Certifications: None.... yet
    WIP: CCNA

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