I'm using an arduino uno, and an 16x2 LCD that is connected to the arduino uno with a 1m long UTP cable to transmit data and as well power the LCD screen.

I used to test my code and my wiring with short wires and everything worked perfectly, as soon as I used the UTP cable to move my lcd a bit away from the arduino, the same code and wiring doesn't work, all i see is gibberish text (nonsense characters on the screen). I have other components in the circuit, but I have disabled them all and checked again (quadruplechecked) everything, including the LCD alone, but the problem remians. I also gave the lcd a whole separate powering line, as I thought it could have run low in energy bcs of other components using the same 5v line.

Anyone has any idea of what could the problem be? Has anyone tried connecting components with UTP cables? Should I maybe use STP instead?


  • What is the protocol you are using? Which wires are you using for what function?
    – Majenko
    Aug 28, 2015 at 14:29
  • possible duplicate of 2,5m cable too long for LCD connected to Arduino UNO?
    – Nick Gammon
    Aug 28, 2015 at 21:02
  • Please try using a multimeter and check the voltage in the + and - wires. Also try wrapping the wires in tinfoil, it should reduce the interference.
    – Avamander
    Aug 29, 2015 at 8:43
  • 1
    Until we know what protocol you are using (I2C? SPI Shift registers? UART?) and which pins you are using on the UTP cable (not all pins are equal - it's the way the wire is made) we can't make any serious recommendations. There are specific things you can do in specific circumstances (decrease pullup resistance for I2C, use the pairs of the UTP properly as pairs with signal/ground, or even generate an LVDS for maximum performance). All depend though on what you are doing and using now.
    – Majenko
    Aug 29, 2015 at 10:04
  • This might be of some help assuming that we are talking about I2C wiring; electronics.stackexchange.com/questions/106265/… Dec 27, 2015 at 22:00

1 Answer 1


Is the cable shielded? Have to performed continuity test on all leads of the cable to ensure there no break internally that could be causing an issue, or a short?

What is the impedance of your total length of cable?

These sorts of checks will help you further narrow down the issue. If you are certain your wiring is correct, then the most probable issue is either a hardware failure (continuity test) a hardware limitation (Too much resistance for accurate data travel) Improper Hardware, unshielded wires can be subject to crosstalk, or signal corruption/distortion due to external signals interfering.

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