Your TV’s RS-232 port is a powerful automation tool – how to unlock it (and what it can do)


Sony Bravia 8 II TV

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With the exception of USB and HDMI inputs, you’ve probably never given much thought to the ports and connections your TV offers, especially once your home theater system is set up. But the RS-232 serial port can be a valuable tool for more advanced tech users looking to create a truly custom home theater or who want total control over their smart devices. 

Also: I changed 13 settings on my TV to dramatically improve its performance – here’s how

With some patience and more than a little know-how, you can create a fully automated home entertainment system with timed content, simultaneous broadcasts to multiple rooms, and even diagnostic testing.  

What is an RS-232 serial port, and what does it do?

Take a peek at the back of your TV, and you may see — among the familiar HDMI and USB connections — an odd 9-pin port that doesn’t match any cable you have in the house (and may look familiar if you used a printer back in the 1990s). This is your TV’s RS-232 serial port, normally reserved for connecting professional calibration and diagnostic tools. 

Technicians at the factory or in a repair shop have special testing devices that plug into the RS-232 port to test signal transmission strength, debug software, and check for electrical damage. 

rs-232gettyimages-1457455797

ChiccoDodiFC / iStock / Getty Images Plus via Getty Images

The RS-232 port can also be used in both smart home and commercial settings by enabling you to connect multiple TVs to a single source for custom broadcasts. Whenever you go to a doctor’s office or an airport where multiple screens show the same reels of advertisements and safety announcements, you’re seeing the RS-232 connection at work. 

Also: The best TVs to buy: Expert tested and recommended

While this port is generally reserved for business use, if you have the money and desire, you can use the RS-232 connection to set up a custom multi-room broadcast system; you can watch the same content in multiple rooms throughout your house in perfect sync, or create custom, curated playlists for your home-based business, kids’ playroom, or your next house party.

Which TVs have an RS-232 port?

While many brands include an RS-232 port in smart TV builds, it’s usually reserved for the higher-end models. Commercial-grade TVs will also include a connection, as they are specifically designed for use in RS-232 broadcast systems. Some midrange models from more established brands like LG may feature an RS-232 connection, but it’s rare to see one on a budget model. 

Using the RS-232 port at home

Using the RS-232 on your TV isn’t for the faint of heart or technology-averse. But if you know how to code, setting up an automated video feed is fairly straightforward. You’ll need either an RS-232 cable or RS-232-to-Bluetooth adapter and a computer. 

Once you’ve got your TV connected to your PC or laptop, you can create code protocols for precision timing, to specify the content to include, and to specify where to broadcast your content. 

Another device you’ll need will be a Serial Port/HDMI matrix. This acts as the central hub for your system, connecting your PC, main TV, and satellite screens to a single switch box for an all-in-one control solution. Matrix receivers offer a range of connectivity options, with some supporting up to 32 separate HDMI inputs and outputs for setting up commercial systems. 

However, for home use, an 8×8 HDMI matrix will be more than enough to handle a casual system. Many HDMI matrix boxes also have Ethernet and Wi-Fi connectivity, so you can stream web content from apps like Netflix and HBO Max, as well as YouTube and Twitch. You can also find models that support Dolby and DTS audio passthroughs for custom sound systems to augment your TV speakers or play separate audio. 

Finding the right programming language

Since each system is unique, you’ll need to check which programming language your devices use to communicate with one another and process audio and visual signals. These programs are often proprietary and require a fair bit of knowledge to properly modify for your particular setup. 

If you need a jumping-off point, you can find step-by-step coding guides for controlling specific brands and device systems on GitHub; coding languages range from HTML and C# to Python and Java (and everything in between), so you shouldn’t have trouble finding a control module that works for you.

Also: Your TV may be tracking your viewing data – here’s how to stop it (beyond disabling ACR)

If you’re looking to monitor your smart TV’s health via the RS-232 port, you can purchase a signal tester for around $20. Many are compatible with Windows, MacOS, and Linux, allowing you to seamlessly integrate your smart TV into your PC setup, no matter which operating system you use. 

An RS-232 tester will check for dead or damaged connector pins, signal strength, and communication between your TV and PC; if any issues arise, you’ll get detailed feedback on the problem for fast troubleshooting and solutions.  

Bottom line

If you are into Home Assistant, Crestron, or Roomie Remote, the RS-232 port is a goldmine. It is significantly more reliable than IR blasters (which can be blocked) or CEC (which is notoriously buggy). Just understand that setting up the RS-232 port to handle your automations or other personalized tasks will take time and learning. 





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Recent Reviews


When you pick out a phone, you’re also picking out the operating system—that typically means Android or iOS. What if a phone didn’t follow those rules? What if it could run any OS you wanted? This is the story of the legendary HTC HD2.

Microsoft makes a mess with Windows Mobile

The HD2 arrives at an unfortunate time

windows mobile 6.5 Credit: Pocketnow

Officially, the HTC HD2 (HTC Leo) launched in November 2009 with Windows Mobile 6.5. Microsoft had already been working on Windows Phone for a few years at this point, and it was planned to be released in 2009. However, multiple delays forced Microsoft to release Windows Mobile 6.5 as a stopgap update to Windows Mobile 6.1.

Microsoft’s plan for mobile devices was a mess at this time. The HD2 didn’t launch in North America until March 2010—one month after Windows Phone 7 had been announced at Mobile World Congress. Originally, the HD2 was supposed to be upgraded to Windows Phone 7, but Microsoft later decided no Windows Mobile devices would get the new OS.

This left the HD2 stuck between a rock and a hard place. Launched as the final curtain was dropping on one OS, but too early to be upgraded to the next OS. Thankfully, HTC was not just any manufacturer, and the HD2 was not just any phone.

The HD2 was better than it had any right to be

HTC made a beast of a phone

HTC HD2 Credit: HTC

HTC was one of the best smartphone manufacturers of the late 2000s and 2010s. It manufactured the first Android phone, the first Google Pixel phone, and several of the most iconic smartphones of the last two decades. Much of the company’s reputation for premium, high-quality hardware stems from the HD2.

The HD2 was the first smartphone with a 4.3-inch touchscreen—considered huge at the time—and one of the first smartphones with a 1 GHz Qualcomm Snapdragon processor. That processor, along with 512GB of RAM, made the HD2 more future-proof than HTC probably ever intended. Phones would be launching with those same specs for the next couple of years.

For all intents and purposes, the HD2 was the most powerful phone on the market. It just so happened to run the most limiting mobile OS of the time. If the software situation could be improved, there was clearly tons of potential.

The phone that could do it all

Android, Windows Phone, Ubuntu, and more

The key to the HD2’s hackability was HTC’s open design philosophy. It had an easily unlockable bootloader, and it could boot operating systems from the NAND flash and SD cards.

First, the community took to righting a wrong and bringing Windows Phone 7 to the HD2. This was thanks to a custom bootloader called “MAGLDR”—Windows Phone 7.5 and 8 would eventually get ported, too. The floodgates had opened, and Windows Phone was the least of what this beast of a phone could do.

Android on the HTC HD2? No problem. Name a version of the OS, and the HD2 had a port of it: 2.2 Froyo, 2.3 Gingerbread, 4.0 Ice Cream Sandwich, 4.1/2/3 Jelly Bean, 4.4 Kitkat, 5.0 Lollipop, 6.0 Marshmallow, 7.0 Nougat, and 8.1 Oreo. Yes, the HD2 was still getting ports seven years after it launched.

But why stop at Android? The HD2 was ripe for all sorts of Linux builds. Ubuntu—including Ubuntu Touch—, Debian, Firefox OS, and Nokia’s MeeGo were ported as well. The cool thing about the HD2 was that it could dual-boot OS’. You didn’t have to commit to just one system at a time. It was truly like having a PC in your pocket, and the tech community loved it.

Do a web search for “HTC HD2” now, and you’ll find many articles about the phone getting yet another port of an OS. It became a running joke that the HD2 would get new versions of Android before officially supported Android phones did. People called it “the phone that refuses to die,” but it was the community that kept it alive.

The last of its kind

“They don’t make ‘em like they used to”

HTC HD2 close up Credit: TechRepublic

The HTC HD2 was a phone from a very different time. It may have gotten more headlines, but there were plenty of other phones being heavily modded and unofficially upgraded back then. Unlockable bootloaders were much more common, and that created opportunities for enthusiasts.

I can attest to how different it was in the early years of the smartphone boom. My first smartphone was another HTC device, the DROID Eris from Verizon. I have fond memories of scouring the XDA-Developers forums for custom ROMs and installing the latest Kaos builds on a whim during college lectures. Sadly, it’s been many years since I attempted that level of customization.

It’s not all doom and gloom for modern smartphones, though. Long-term support has gotten considerably better than it was back in 2010. As mentioned, the HD2 never officially received Windows Phone 7, and it never got any other updates, either. My DROID Eris stopped getting updates a mere eight months after release.

Compare that to phones such as the Samsung Galaxy S26, Google Pixel 10, and iPhone 17, which will all be supported through 2032. You may not be able to dual-boot a completely different OS on these phones, but they won’t be dead in the water in less than a year. We will likely never see a phone like the HTC HD2 from a major manufacturer again.

HTC Droid Eris


A Love Letter to My First Smartphone, the HTC Droid Eris

No, not that DROID.



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