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I have just bought an HDMI 10m cable and of course it comes with male plugs on both ends, and that's because almost all HDMI devices have a female socket.

But why is that? I can understand that when a sender-receiver difference is not clear that can work, e.g. the always wrong type RS232 connector, but for HDMI there clearly is a device that produces video, and a device that consumes it, end of story. Of course there's some sort of symmetric communication going on but the data flow is pretty clear.

This came to my mind since you can't make longer chords just by plugging two extenders one in another, as you would do with mains extenders. You can yell at me that's out of spec, but female to female adapters exist and who the hell cares about the standard anyway?

Some of the reasons that came to mind:

  • you only need to design female pcb/panel mound connectors, and male cable connectors
  • you can use tha same physical connector both as an input and an output (maybe capture video on a VGA?)
  • ?

I'm hoping not to get opinion based close votes since I (want to) believe that there's a perfectly legitimate reason behind this choice.

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  • \$\begingroup\$ Why is this an issue? Everyone's life is simpler if there's only one kind of plug and one kind of socket. (Except of course, that we now have mini-HDMI and micro-HDMI, not to mention DisplayPort ...) \$\endgroup\$ – Dave Tweed Jan 23 '15 at 12:31
  • \$\begingroup\$ Well I'm not saying it's an issue, I'm wondering about the design metrics that pushed towards this decision. First thing that came to my mind is that you can't cascade cables, of course that's just a minor issue but you know... And of course I can plug two producers (output) together, nothing would probably happen but that's thanks to a more complicated circuitry/handshake/whatever... \$\endgroup\$ – Vladimir Cravero Jan 23 '15 at 13:00
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    \$\begingroup\$ Maybe it's because designers favor flush surfaces for their devices, without any protruding metal connectors. \$\endgroup\$ – JimmyB Jan 23 '15 at 13:54
  • \$\begingroup\$ You can certainly have a non protrunding male connector, as any usb receptacle. \$\endgroup\$ – Vladimir Cravero Jan 23 '15 at 13:57
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    \$\begingroup\$ Your premise isn't fully true. The google chromecast and similar are counterexamples which have male HDMI connectors, as they are intended for direct connection to another device without a cable. \$\endgroup\$ – Chris Stratton Jan 23 '15 at 16:08
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from http://www.hdmi.org/learningcenter/faq.aspx#94

Q. How will HDMI change the way we interface with our entertainment systems? The most tangible and immediate way that HDMI changes the way we interface with our components is in the set-up. One cable replaces up to 11 analog cables, highly simplifying the setting up of a home theater as well as supporting the aesthetics of new component design with cable simplification.

Next, when the consumer turns on the HDMI-connected system, the video is of higher quality since the signal has been neither compressed nor converted from digital to analog and back.

Lastly, because of the two-way communication capabilities of HDMI, components that are connected via HDMI constantly talk to each other in the background, exchanging key profile information so that content is sent in the best format without the user having to scroll through set-up menus. The HDMI specification also includes the option for manufacturers to include CEC functionality (Consumer Electronics Control), a set of commands that utilizes HDMI’s two- way communication to allow for single remote control of any CEC-enabled devices connected with HDMI. For example, CEC includes one-touch play, so that one touch of play on the DVD will trigger the necessary commands over HDMI for the entire system to power on and auto-configure itself to respond to the command. CEC has a variety of common commands as part of its command set, and manufacturers who implement CEC must do so in a way that ensures that these common command sets interoperate amongst all devices, regardless of manufacturer.

It's pretty clear that in the standard, they were trying to make sure that you would ALWAYS have the right cable when trying to assemble consumer-grade AV systems, and one way to do that is to have one cable style. Also, they want to play up the two-way communication features of HDMI.

Of course, that's speculation, but I can honestly assert that I've never cursed at HDMI connections anywhere near as loudly as I've cursed at USB connections.

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This answer probably has nothing to do with why the HDMI connectors are the way they are, but in Professional Audio, we always try to put female multipin connectors on the boxes / enclosures and have male pins on the cables. The reason is that pins do get bent and broken and it's a lot easier to just grab a new / spare cable when that happens.

Same with recent computer VGA connectors and cables: these used to be mixed male / female but seem to have changed over the past decade or so to be female connectors on the devices and male connectors at both ends of the cable.

Personally, I quite like that the HDMI cables are symmetrical and I don't have to worry about which end is which when crawling behind someone's entertainment center trying to plug stuff in.

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Because it might be due to the design of the product. as if it has an male port it has to be pointing out (that is it should project out) of the product which may get damaged while using or might injure someone if the rub towards the machine.

so inorder to safeguard the plug they designed it to use female port.

think of it if you have a male port in your wall switch board. wat will happen.??

while crossing it you might hit it or you will get shock. and if the male port is setup in the machine, it needs a lot of space which is more than female socket.

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  • \$\begingroup\$ A male or female plug take exaclty the same space for the very definition of plug. The part about wall plugs does not apply in any way to my question. \$\endgroup\$ – Vladimir Cravero Jan 23 '15 at 14:25
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I suspect the most likely reason is convenience. For many people, setting up a home AV system is an exercise in confusion and frustration. Imagine being on your hands and knees peering behind a Blu-ray player that you can barely see because the top of the TV stand is blocking the light. Now imagine that you have no idea what's supposed to connect to what. Maybe there's a huge rat's nest of cables, maybe there's a receiver, maybe there are three game consoles. Do you want to have to worry about cable gendering? Think about how many problems people have with USB connectors under the same circumstances.

Something like "the male end of the cable points towards the video source" sounds simple to people like us, but if you say something like that to the general public, you've already lost a large fraction of your audience.

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This mostly comes down to common sense engineering, and a little bit of status quo. It is difficult to make a connection between two completely identical pieces, so you specialize them. Arbitrarily, you call one female and one male - one goes in the other. The pins that stick out are easier to break so you put it in the part that is easier to replace - the cable. Such is true of VGA, F connectors for coaxial cables, USB, and now HDMI. Given the rugged design of the hdmi jack on the cable, the pins aren't particularly at risk - but if we had reversed those exact sockets, the cable end would get unwieldy, and we still would have called it male, because it goes into the other side.

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