We’re moving away from dedicated ports more and more, simply because the size of current devices don’t allow that many inputs and outputs. That means we depend more and more on adapters, which can be a good or a bad thing depending on the situation, and the cost of the adapters. When buying adapters, though, there are a few things you might want to keep in mind.

Don’t put pressure on ports by choosing the wrong adapter design

What prompted me to write an article about this topic was seeing this adapter on DealExtreme. It’s small, elegant, and perhaps the worst adapter I have ever seen. Why? HDMI cables are huge. Freaking huge. The cable is thick, the plug is big, and their so rigid you can almost use them as weapons. When you then plug such a cable into a tiny microHDMI port via an adapter that doesn’t have its own small extension cable to allow for some play when the HDMI cable moves, you’re putting all the pressure coming from that unruly cable on that tiny port. It’s not designed for that. Heck, microUSB is infamous for breaking from normal use with normal cables, and microHDMI isn’t much different. There’s a reason why official HDMI adapters for ports that small have a thinner, flexible cable going into the final plug, allowing for some play.

The same is of course true for other plug types than HDMI, as many adapters are there for connecting to larger connectors. When it comes to USB host adapters for microUSB, for instance, the same idea with a flexible cable between the two ends of the adapter applies. Larger universal connectors, like 30 pin connectors, don’t have the same need for a flexible part on some adapters- exampled by Apple’s Camera Connection Kit, which doesn’t have the flexible part that the company’s HDMI adapter has.

Point being, don’t buy adapters and company that are small without giving this some thought. For the most part it’s third party adapters that are as poorly designed as the example above, but that doesn’t necessarily mean that official is best.

Some adapters work across devices, some don’t

One thing I see a lot of is people wondering if an adapter for device A is compatible with device B. That’s a complicated question to answer, because it varies. As the first and foremost rule, though, don’t assume that they are. I’ve seen people ruin the connector port of their device because they tried to fit Apple accessories in where they didn’t belong, all because the connector looked the same. Research is your friend in these situations, and make sure you do the research before you try anything.

It’s actually quite ridiculous how few true standards we have. MHL (microUSB to HDMI) is for the most part universal, but then there are devices like the Galaxy S III. The SD card “standard” consists of no less than three physical standards, which work with one another through adapters, and three version standards that are only forwards compatible, meaning that old cards work in new devices (SD->SDHC->SDXC). Three types of physical USB connectors, three USB versions. Then you have four pin audio connectors, which some devices use for the microphone, some for remote control, some for charging, and some for data transfer- or a mix of the above. Some older Galaxy Tab accessories work with newer devices, but not the other way. It really is a mess, which is why there really is no universal answer other than “Google before you try.”

Don’t confuse physical connectors with software support

There’s a rather unfortunate misconception when it comes to the difference between a physical connector and software support, especially around USB. USB is a connector type, and doesn’t mean that anything with a USB connector automatically works on something with a USB port. Take the iPad as an example. The Camera Connection Kit is a neat accessory that has a USB port, but it doesn’t support the same things as a computer USB port. It supports media transfer, USB audio devices, USB keyboards, and even USB MIDI devices, but it does not support UMS (Universal Mass Storage). UMS is what many people actually mean by “USB support” – namely the ability to connect things like flash drives in order to access the files on that drive (for the record, this is possible through jailbreaking). In other words, the iPad has a USB adapter, but that adapter doesn’t give you USB support.

Android, on the other hand, supports UMS through USB host adapters. It also supports keyboards and mice, and some newer devices even support game controllers and audio devices, though that’s not very common right now.

Another thing to keep in mind is the power consumption of devices you want to connect via USB. Standard USB is 5 volts, 500 milliampere. The 5V is the same for all USB ports, but the mA rating differs. Mobile devices often can’t deliver more than 50-70mA through USB host adapters, which means that only very low power USB devices will work. Simple keyboards and flash drives will likely work, but add too many flashing LEDs or other power hungry features, and they most likely won’t.

Finally, don’t confuse a device’s ability to connect to a computer via USB with its ability to have other devices connect to it over USB. USB host, which I’ve referred to several times already, is when a mobile device allows other devices (like flash drives) to connect to it. More and more devices have this ability, and they normally do it using an adapter for the normal USB port, but that does in no way mean that you automatically have USB host capability. Furthermore, don’t confuse adapters designed to allow a device to connect to a different type of USB cable with one designed to enable USB host. USB host cables are marked as such, and just because you can make the physical adaptation with other products, doesn’t mean it will work.

The same concept of hardware/software separation also goes for other things than USB. 4 pin audio jacks with buttons for remote control don’t necessary work across devices, at least not across OSes. That’s technically a hardware difference, not a software difference, but it’s internal hardware so I’ll classify it as close enough. With HDMI, you have to worry about things like HDCP when you need to connect something, and you might find that some monitors simply can’t play copyrighted content.