Are HDMI Cables Hot Swappable? (+ Is it Safe to Do?)

Maybe you’re tired of playing your newest Xbox game and would rather play on that new PS5 Santa brought you. Or it might be that your television has fewer HDMI ports than you need for all the accessories you have. What’s a techie to do?

There’s often a need to do an HDMI cable swap from one device to another, like a gaming system switch up, and you would rather not have to take the time to power down your devices. 

Making a quick switch without powering down HDMI-connected devices is referred to as “hot swapping” or “hot plugging.”

HDMI cables, in theory, support hot swapping because of a specific pin in the female connector referred to as the hot plug detect (HPD). When an HDMI cable is unplugged, this pin is the first to be disconnected. The HPD pin communicates to the output and input devices to cease working, thus safely enabling hot swapping.

To better understand the ins and outs of hot swapping HDMI cables, you need to comprehend the form and function of HDMI cables and the various features that allow for hot swapping to be performed safely.

Hot swapping is a convenient characteristic of most modern devices that allows for a display to be plugged into a device while both are powered up. Hot swapping entitles both machines to become instantly active with all the proper display settings.

Hot swapping is made possible by three key features:

•       Hot plug detection (HPD)
•       Display data channel (DDC)
•       Extended display identification data (EDID)

This article will cover how HDMI cables work and the features allow hot swapping to take place.

What is HDMI cable hot swapping?

Hot swapping, or hot plugging, is the ability to add or remove a device from a display system without having to power down either device. “Hot” essentially means that the HDMI port is active during the plugging procedure.

If done correctly, with a functional HDMI cable and issue-free ports, hot swapping will not cause any issues to either device. However, if the HDMI cable is impaired in any way or connected devices have loose HDMI ports or grounding problems, the device damage risk from hot swapping is high.

How do HDMI cables work?

High-definition multimedia interface (HDMI) technology transfers data from one location to another via transition-minimized differential signaling (TDMS). TDMS protects data from degrading while traveling the cable’s length from one apparatus to another.

The device sending the information will encode the data by reducing transmission numbers. This data encryption helps to protect signal quality and reduces the chances of information degradation.

One of the intertwined pairs of cables carries the initial signal as data is transferred. In contrast, the other line carries an inverted copy of the data transmission. Once information is delivered to the receiving device, the HDMI will measure the difference between the two transmissions. It will use gained information to make up for the signal loss incurred during the process.

With all of that technical jargon said, HDMI cables are an utterly digital data transfer medium. They maintain perfect picture transfer across multiple processes. Plus, HDMI is a single cable system (can you say EASY?).

What is hot plug detection (HPD)?

HDMI cables have a specific feature that facilitates hot swapping between two connected devices called hot plug detect (HPD).

The hot plug detect can be found on the nineteenth pin of the female end of the HDMI connector. The HPD is the first pin disconnected when unplugged and communicates to the input and output devices to cease data transfers.

When reconnected, the HPD is the first pin to initialize contact and restart data transfer between the two devices. Any damage to the HPD pin will result in a hot swapping detection failure and possible damage to your devices.

What is display data channel (DDC)?

The display data channel (DDC) is used to describe both the process and physical route used by the input and output devices connected by an HDMI cable.

The DCC is typically found in one single pin on the HDMI interface and bears the extended display identification data (EDID).

What is extended display identification data (EDID)?

Extended display identification data (EDID) is data supplied by the display to define its needs and abilities to the source device. EDID will include details such as maximum resolution, color spaces, refresh rate, serial number, and manufacturer.

Conclusion 

Generally speaking, hot swapping HDMI cables is not only time-saving but also safe given that both devices are structurally sound and designed for hot swapping. If you are not sure how your devices will react to hot swapping, simply turn off your devices before plugging or unplugging any HDMI cables.

If you feel confident that both your HDMI cable and attached devices are hot swapping-safe and have performed the action multiple times before, go ahead and hot swap – you’ll be causing no harm!