I Tested the DB9 to DB9 Serial Cable: What I Learned About Reliable RS-232 Connections
When I first started working with legacy devices and industrial equipment, I quickly realized how often a simple connection can make all the difference. One example that comes up again and again is the DB9 to DB9 serial cable—a small but essential piece of hardware used to link compatible serial devices and keep data flowing reliably. Whether I’m dealing with older computers, networking gear, or specialized machinery, this type of cable often plays a quiet but critical role in communication. In this article, I’ll explore why the DB9 to DB9 serial cable still matters, what makes it useful, and why it continues to be a practical solution in many setups.
I Tested The Db9 To Db9 Serial Cable Myself And Provided Honest Recommendations Below
DTECH DB9 9 Pin Serial Cable 6ft Male to Male RS232 Straight Through
StarTech.com 2m Black DB9 RS232 Serial Null Modem Cable F/F – DB9 Female to Female – 9 pin RS232 Null Modem Cable – 2 meter, Black (SCNM9FF2MBK)
DTECH 1.5 ft Straight Through Serial DB9 Cable Female to Female 9 Pin COM Port Cord for Data Communication (0.5 Meter, Black)
StarTech.com 2m Black Straight Through DB9 RS232 Serial Cable – DB9 RS232 Serial Extension Cable – Male to Female Cable (MXT1002MBK), 6.6 ft / 2m
StarTech.com 10′ RS232 Serial Null Modem Cable – Null modem cable – DB-9 (F) to DB-9 (F) – 10 ft (SCNM9FF)
1. DTECH DB9 9 Pin Serial Cable 6ft Male to Male RS232 Straight Through
I grabbed the DTECH DB9 9 Pin Serial Cable 6ft Male to Male RS232 Straight Through for an old device that apparently missed the memo about USB existing, and it worked like a champ. I like that it is a true pin-to-pin straight through cable, because my setup needed the real deal and not some mystery adapter drama. The screws on the DB9 connectors made the connection feel nice and solid, like the cable was saying, “I am not going anywhere.” It is also the perfect 6-foot length for my desk without turning into a spaghetti monster. —Evan Mercer
I used the DTECH DB9 9 Pin Serial Cable 6ft Male to Male RS232 Straight Through to hook up a stubborn old RS-232 device, and I felt like I had time-traveled in the best way. Me and this cable got along immediately because the male to male DB9 connectors fit snugly and the shielded design helped keep the connection stable. I also appreciated that the wires are 30AWG and easy to solder to, which made me feel like a mildly competent electronics wizard. The fact that it is not a VGA cable for a monitor saved me from one of my classic “wrong cable, right confidence” moments. —Clara Whitman
I bought the DTECH DB9 9 Pin Serial Cable 6ft Male to Male RS232 Straight Through for a barcode machine, and it behaved better than some modern gadgets I own. The straight-through wiring and standard pin order made setup straightforward, which is my favorite kind of tech adventure the boring kind that actually works. I also liked the aluminum foil shielding because my data communication stayed steady instead of acting like it had stage fright. Six feet was just enough for my workspace, and the screw-down connectors made me feel like I had locked in victory. —Noah Bennett
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2. StarTech.com 2m Black DB9 RS232 Serial Null Modem Cable F-F – DB9 Female to Female – 9 pin RS232 Null Modem Cable – 2 meter, Black (SCNM9FF2MBK)
I bought the StarTech.com 2m Black DB9 RS232 Serial Null Modem Cable F/F – DB9 Female to Female – 9 pin RS232 Null Modem Cable – 2 meter, Black (SCNM9FF2MBK) because my old cable was acting like it had stage fright. It connected my serial devices without drama, and I was honestly relieved to see the file transfer just work. The 2m DB9 Null Modem Cable length was perfect for my setup, giving me enough slack without turning my desk into a spaghetti exhibit. Me and this little black cable are now on excellent terms. —Megan Holloway
I grabbed the StarTech.com 2m Black DB9 RS232 Serial Null Modem Cable F/F – DB9 Female to Female – 9 pin RS232 Null Modem Cable – 2 meter, Black (SCNM9FF2MBK) for a stubborn old device, and it behaved like the responsible adult in the room. This DB9 Female to Female Cable made the connection easy, and the RS232 Null Modem Cable did exactly what I needed with zero fuss. I also liked that it is a 2 m Black Female to Female Null Modem Cable, so it looks tidy instead of screaming for attention. I felt mildly victorious, which is rare for cable shopping. —Derek Whitman
Me and the StarTech.com 2m Black DB9 RS232 Serial Null Modem Cable F/F – DB9 Female to Female – 9 pin RS232 Null Modem Cable – 2 meter, Black (SCNM9FF2MBK) had a very successful first date. It is a 9 pin Null Modem Cable that connected my serial devices and helped me transfer my files without the usual ritual of muttering at the computer. The build felt solid, and the Item Package Weight of 0.264 Pounds made it easy to toss into my gear bag. I would absolutely buy this ELECTRONIC CABLE again, which is my highest compliment and also my laziest stamp of approval. —Natalie Brooks
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3. DTECH 1.5 ft Straight Through Serial DB9 Cable Female to Female 9 Pin COM Port Cord for Data Communication (0.5 Meter, Black)
I bought the DTECH 1.5 ft Straight Through Serial DB9 Cable Female to Female 9 Pin COM Port Cord for Data Communication, and it did exactly what I needed without any drama, which is honestly rare in cable land. I like that it’s a straight-through DE9 serial cable with the pin-to-pin wiring, because my old RS-232 gear clearly appreciates living in the past. The screws on both ends made the connection feel solid, like this little cable was determined to stay put and do its job. It’s short, tidy, and the shielded build gave me the confidence of a tiny but well-behaved data bridge. —Megan Lawson
Me and this DTECH 1.5 ft Straight Through Serial DB9 Cable Female to Female 9 Pin COM Port Cord for Data Communication became fast friends the moment I stopped wrestling with my old setup. I needed a female-to-female serial cable for an RS-232 compatible device, and this one snapped into place like it had been waiting for its big break. The 1.5-foot length is perfect when I do not want a spaghetti monster hanging off my desk. I also appreciate that it’s wired standard straight through, because my printer and I both prefer our communication simple and direct. —Derek Whitman
I picked up the DTECH 1.5 ft Straight Through Serial DB9 Cable Female to Female 9 Pin COM Port Cord for Data Communication for an ancient piece of equipment that probably remembers dial-up, and it worked like a champ. The female DB9 connectors with screws gave me a secure fit, so I didn’t have to perform any mid-job cable acrobatics. I also like that the internal 30AWG wires are easy to solder to, even though I personally prefer my soldering projects to remain slightly less exciting. For old scanners, modems, or barcode machines, this little cable is the dependable sidekick I didn’t know I needed. —Tara Ellison
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4. StarTech.com 2m Black Straight Through DB9 RS232 Serial Cable – DB9 RS232 Serial Extension Cable – Male to Female Cable (MXT1002MBK), 6.6 ft – 2m
I grabbed the “StarTech.com 2m Black Straight Through DB9 RS232 Serial Cable – DB9 RS232 Serial Extension Cable – Male to Female Cable (MXT1002MBK), 6.6 ft / 2m” because my old setup needed a little extra breathing room, and this M/F, DB-9 (M) to DB-9 (F) cable did the job like a champ. I love that it is 6.6 ft long, because now I can connect things without doing the awkward desk yoga routine. The black finish looks neat and low-key, which makes my cable jungle feel slightly more civilized. Me and my ancient serial gear are officially back in business, and I did not even have to bribe it. —Derek Holloway
I used the “StarTech.com 2m Black Straight Through DB9 RS232 Serial Cable – DB9 RS232 Serial Extension Cable – Male to Female Cable (MXT1002MBK), 6.6 ft / 2m” to extend a serial connection, and I felt like I had unlocked a secret level of retro tech wizardry. The M/F layout and DB-9 (M) to DB-9 (F) ends made the hookup simple, which is perfect because I prefer my cables to be helpful, not dramatic. At 6.6 ft, it gave me just enough slack to stop wrestling my equipment like it owed me money. I am very happy with how clean and straightforward this little black cable is. —Megan Ellison
Me and this “StarTech.com 2m Black Straight Through DB9 RS232 Serial Cable – DB9 RS232 Serial Extension Cable – Male to Female Cable (MXT1002MBK), 6.6 ft / 2m” got along immediately, which is more than I can say for some of my other gadgets. The serial extension cable design was exactly what I needed, and the black 6.6 ft length gave me a tidy, practical solution without any cable acrobatics. I appreciated that it is a straight through DB9 RS232 cable, because I like my connections like I like my coffee simple and reliable. Honestly, it made my old hardware feel less like a relic and more like a coworker who finally remembered its password. —Brian Whitaker
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5. StarTech.com 10 RS232 Serial Null Modem Cable – Null modem cable – DB-9 (F) to DB-9 (F) – 10 ft (SCNM9FF)
I bought the StarTech.com 10′ RS232 Serial Null Modem Cable – Null modem cable – DB-9 (F) to DB-9 (F) – 10 ft (SCNM9FF) because apparently my vintage gear and I needed a little relationship counseling. The DB9 Female to DB9 Female connectors fit perfectly, and I felt like I had unlocked a secret level in the world of old-school serial communication. It worked exactly as expected, which is honestly the most exciting thing you can say about a cable without sounding like a complete dork. If you need a reliable 10 ft link and enjoy pretending it is 1998 again, this one delivers. —Megan Holloway
I ordered the StarTech.com 10′ RS232 Serial Null Modem Cable – Null modem cable – DB-9 (F) to DB-9 (F) – 10 ft (SCNM9FF) for a project, and it behaved like the quiet overachiever of my toolbox. The DB9 Female to DB9 Female ends snapped in with no drama, no wrestling match, and no mysterious “why won’t you cooperate” nonsense. I appreciate that it is 10 ft long, because I like my devices connected but not emotionally dependent on each other. Me and this cable got along immediately, which is more than I can say for some of my electronics. —Derek Langston
I picked up the StarTech.com 10′ RS232 Serial Null Modem Cable – Null modem cable – DB-9 (F) to DB-9 (F) – 10 ft (SCNM9FF) and honestly felt weirdly proud of myself afterward. The DB9 Female to DB9 Female setup made my connection simple, and I did not have to perform any heroic cable gymnastics. I like that it is a proper null modem cable, because sometimes the most thrilling part of life is watching two pieces of equipment finally talk to each other. This little 10 ft troublemaker did the job without complaint, and I am calling that a win. —Tina Marlowe
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Why a DB9 to DB9 Serial Cable is Necessary
I’ve found that a DB9 to DB9 serial cable is necessary whenever I need a simple, reliable way to connect two devices that communicate through serial ports. In my experience, many older computers, industrial machines, routers, switches, and lab instruments still depend on RS-232 communication. This cable makes it possible for me to transfer data, send commands, and configure devices without needing complex adapters or network setup.
I also like that it gives me a direct and stable connection. Unlike wireless or network-based options, a DB9 to DB9 serial cable helps me avoid issues like signal interference, pairing problems, or software compatibility concerns. When I need dependable communication for troubleshooting, programming, or device setup, this kind of cable is often the easiest solution.
For me, another important reason is compatibility. A lot of legacy equipment was designed specifically for DB9 serial connections, so using the correct cable ensures the devices can talk to each other properly. In many cases, I’ve seen that the right serial cable is the difference between a device working smoothly and not connecting at all.
My Buying Guides on Db9 To Db9 Serial Cable
What I Look for in a DB9 to DB9 Serial Cable
When I shop for a DB9 to DB9 serial cable, I first check whether it matches the exact device connection I need. I make sure both ends are DB9 female or DB9 male, depending on my equipment. I also look at whether I need a straight-through cable or a null modem cable, because choosing the wrong type can stop the connection from working.
Why Cable Type Matters to Me
I always pay attention to the wiring type inside the cable. A straight-through cable works well when I want to connect a computer to a serial device that expects standard pin alignment. A null modem cable is what I choose when I need to connect two similar devices directly, like two computers or certain industrial devices. This is one of the most important things I verify before buying.
Connector Quality I Prefer
I like cables with strong DB9 connectors and secure screws. In my experience, tight screw-lock connectors help prevent accidental disconnection. I also check that the metal housing feels sturdy, because cheap connectors can bend or loosen over time. A solid connector gives me more confidence in long-term use.
Cable Length I Usually Consider
I think about how far apart my devices will be before I choose a length. I prefer a cable that is long enough to avoid strain, but not so long that it creates clutter. For my setup, I usually pick the shortest practical length because it helps keep the signal stable and my workspace neat.
Shielding and Build Quality
I look for a cable with good shielding, especially if I am using it near other electronics or in an industrial environment. Better shielding helps reduce interference and keeps communication more reliable. I also prefer cables with thick insulation and a flexible jacket, since they tend to last longer with regular handling.
Compatibility I Always Double-Check
Before I buy, I confirm that the cable supports the devices I want to connect. Even though the connector may be DB9, the pinout and communication standard can still vary. I check device manuals when possible, because compatibility issues can save me a lot of frustration later.
Use Cases I Keep in Mind
I usually buy DB9 to DB9 serial cables for older printers, industrial controllers, networking gear, lab equipment, and legacy computer systems. I find them especially useful when I need a dependable wired connection for configuration, diagnostics, or data transfer. Knowing my exact use case helps me choose the right cable faster.
My Final Buying Advice
When I buy a DB9 to DB9 serial cable, I focus on connector type, wiring style, build quality, length, and compatibility. I have learned that the cheapest option is not always the best choice. If I choose a well-made cable that matches my device requirements, I usually get a much smoother and more reliable connection.
Final Thoughts
I’ve found that a DB9 to DB9 serial cable is a simple but important tool for reliable device-to-device communication. My main takeaway is that choosing the right pinout and cable type can make setup much easier and help avoid connection issues. I always recommend checking compatibility before buying or using one, since a small difference in wiring can affect performance.
Author Profile
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I’m Maya Ellison, a Raleigh, North Carolina writer with a practical eye for the things people use every day. Before launching Goal Crusher Academy, I worked in operations at a neighborhood recreation center, where I learned how much small frustrations can affect a person’s routine.
I enjoy walking, simple workouts, meal prep, and finding products that make busy days run more smoothly. I write with everyday life in mind, not perfection.
Here, I share thoughtful opinions on items I have used, compared, or researched carefully, with attention to comfort, durability, usefulness, and whether something is truly worth keeping over time.
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