I’m trying to send serial port output over a Telnet connection but I’m not sure how to set this up. I need to access my device remotely through Telnet using data from its serial port. Has anyone done this successfully? Any software or configuration tips would be appreciated.
You want to pipe your serial port output over Telnet, basically turning your serial device into something you can access remotely as if it were plugged physically in front of you? Trust me, you’re not alone—this one trips up pretty much everyone at some point.
Here’s what actually works: you need something in the middle to bridge your local serial port and a Telnet (TCP/IP) session. The classic DIY way on Linux is with socat (or sometimes ser2net), but it can get funky if you’re not comfy with command lines. In essence, you set up socat like this:
socat tcp-l:23,reuseaddr,fork file:/dev/ttyS0,raw,echo=0,b115200
This opens up TCP port 23 (Telnet default) and connects it to your serial port (/dev/ttyS0 at 115200 baud in this case).
But if you’re on Windows or you want it to be graphical, reliable, and genuinely “it just works” (plus with bonus features), check out Serial to Ethernet Connector. This app lets you share any local COM port to the network over TCP/IP—including via the Telnet protocol! You can access and manage serial devices remotely exactly as if they were local—a ton easier and way more robust than wrestling with scripts. Plus, if you’re working in a mixed environment (Windows ↔ Linux), it saves a lot of headache because you get everything set up via a UI.
If you want to dive into a full comparison of different methods, or just a step-by-step on Windows OR Linux, this deeper guide’s not bad: setting up Telnet access for serial-connected devices.
To round off: “Redirect serial port output to Telnet” usually involves:
- Running a redirector tool (software/utility/app)
- Forward serial data over TCP/IP
- Connecting with a remote Telnet client to the provided port/IP
Trying to homebrew this with netcat or whatever is doable, but why torture yourself when there’s a purpose-built tool? Serial to Ethernet Connector will save you hours (and probably your sanity).
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List time. Here’s what’s missing in most of these “redirect serial port to Telnet” threads: they all jump straight to socat or “go download XYZ.” @nachtdromer’s got most of it covered for Linux, but honestly that only gets you halfway there in real-world multi-user or mixed-OS scenarios. I’ve lost whole afternoons trying to kludge netcat into this, then hitting stupid stumbling blocks like failed handshakes or random disconnects nobody warns you about.
Breaking it down—here are your actual choices (pain scale included):
-
socat/ser2net (Linux):
- Pros: Free, flexible, big in sysadmin-land.
- Cons: Nightmares with baud rates, permissions, and if you want it cross-platform… forget it.
- Pain scale:
-
Netcat/MSYS hackery:
- Pros: Fun if you like self-torture.
- Cons: Practically guaranteed to break when your boss shows up.
- Pain scale:
-
Serial to Ethernet Connector (Windows & Linux):
- Pros: Insanely easier. Lets you map that old-school COM port practically anywhere over TCP/IP—and it “just works,” even with info-dense stuff like secure ID badges or barcode readers. Remote connect from another box with a Telnet client, and it’ll look & feel local.
- Cons: Not open source, but you save your sanity.
- Pain scale: (if even that)
Also, if you’re hearing the phrase “COM port Redirector” around, that’s basically an app that mirrors or extends your computer’s serial (COM) port data over a network. The remote system can access and manage serial devices just like they were plugged in locally—think of it as turning your hardware’s serial output into a globally reachable virtual device. If you want to see what I mean, scroll through some options using this link for easy remote access to your serial ports—there’s no shortage of tools but only a few actually make it hassle-free.
My take? Running command line scripts is cool for flexing, but honestly, Serial to Ethernet Connector is a game-changer for reliability and cross-platform pain relief. And yes, I may have a few gray hairs from trying out every “open source” angle first. Don’t be me.