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TTL levels — Parallax Forums

TTL levels

GiuseppeGiuseppe Posts: 51
edited 2009-06-12 19:15 in BASIC Stamp
How far can ttl levels travel without lose in transmission quality?

Comments

  • GiuseppeGiuseppe Posts: 51
    edited 2009-06-10 02:12
    nevermind just found it, it is 10 feet max
  • JonathanJonathan Posts: 1,023
    edited 2009-06-10 13:33
    in practice I have gotten over 50 feet. However, it depends on local noise, what kind of cable you use, how fast you are sending data etc.

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    www.madlabs.info - Home of the Hydrogen Fuel Cell Robot
  • GiuseppeGiuseppe Posts: 51
    edited 2009-06-10 13:48
    what cable did you use in practice?
  • JonathanJonathan Posts: 1,023
    edited 2009-06-10 14:21
    I used a shielded, four conductor cable. I was (am, it's running as I write) only running at 9600 baud. I'm sure it would run faster than that, but the device I am talking to can only run at 9600.

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    www.madlabs.info - Home of the Hydrogen Fuel Cell Robot
  • GiuseppeGiuseppe Posts: 51
    edited 2009-06-12 18:45
    Thanks for the info
  • Phil Pilgrim (PhiPi)Phil Pilgrim (PhiPi) Posts: 23,514
    edited 2009-06-12 19:15
    It also helps to terminate the cable on the receiving end with a resistor network. For TTL signal levels, a 180R resistor to +5V and a 390R resistor to ground is typical. This helps to eliminate the effects of reflections, ringing, and noise.

    -Phil
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