What Is the Maximum Length of an HDMI Cable to Mirror iOS Devices?

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Level 3

754 points

What Is the Maximum Length of an HDMI Cable to Mirror iOS Devices?

I have used 15' HDMI 1.4 cables (latest HDMI technology) with an iPhone 5 and 5s frequently with no interruptions and no apparent quality degradation.

Yesterday I tested a 25' HDMI 1.4 cable with my iPhone 5s and it would not work, though the cable worked fine between a laptop and the same big screen TV.

Therefore, we can surmise the maximum length is something above 15', but below 25'.

Has anyone successfully mirrored an iOS device with a cable longer than 15'?

iPhone 5s, Windows 7, iOS 8.1, iTunes, QuickTime Pro

Posted on Oct 25, 2014 12:35 PM

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Answer 1

cyberbiker Author

Level 3

754 points

Oct 25, 2014 5:06 PM in response to cyberbiker

Here's the key information on max HDMI cable length. The reference is at the bottom.

Basically, for cable of the same wire alloy, the width or AWG (American Wire Gauge) and number of intermediate connections is key.

As the length of a wire increases, so does the overall resistance of the wire. Increased resistance means decreased current capacity and therefore decreased bandwidth in HDMI terms. Additionally, if you are installing a repeater device, such as an AV receiver, an HDMI switch or splitter, or anything else in between, you should consider that each connection adds some amount of resistance to the total connection.

Wire gauge directly relates to the amount of electrical current that can be carried on the wire. The larger diameter of wire, the more current it can carry. In terms of HDMI this means that a larger gauge wire (smaller AWG number) is capable of higher bandwidth than a smaller gauge (larger AWG number).

The cutoff points for High Speed HDMI Cables of each AWG rating are:

28 AWG = maximum 10 feet

26 AWG = maximum 12 feet

24 AWG = maximum 15 feet

22 AWG = maximum 25 feet

http://www.monoprice.com/home/home.asp?pn=help&idx=12

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