Need a serial to Ethernet connector recommendation

Networking
1

I’m working on an older device that only has a serial RS-232 port, but I need to get it onto my Ethernet network for remote access and monitoring. I’m a bit lost on which serial-to-Ethernet connector or adapter is reliable, secure, and easy to configure for this kind of setup. Can anyone recommend specific models or features I should look for, and share any setup tips or pitfalls to avoid?

2

If you just need to get an old RS‑232 box onto Ethernet for remote access, you’ve basically got 3 routes:

  1. Dedicated hardware device server

    • Look for “serial device servers” or “RS‑232 to Ethernet converters.”
    • Lantronix UDS series, Moxa NPort, and USR-TCP232 (cheaper) are common.
    • Pros: rock solid once configured, hardware watchdogs, DIN rail mounting, can handle 24/7 uptime.
    • Cons: Cost more than the super cheap adapters, web UI can be clunky, and you’ll be living in “TCP server / client / RFC2217” config hell for a bit.

  2. PC in the middle with software

    • If you already have a Windows machine near the device, you can plug the RS‑232 into a normal USB serial adapter, then use software that turns that COM port into a network service.
    • That is exactly where a Serial to Ethernet Connector solution makes sense.
    • It creates virtual COM ports and shares physical serial ports over LAN or even the internet, so remote apps think they are talking to a local COM port when actually it is traveling over TCP/IP.
    • Check out something like share and manage serial ports over Ethernet which basically lets you:
      • Map a remote serial port to a local virtual COM port
      • Use encryption and access control
      • Work with multiple devices and ports at once
    • Pros: Super flexible, easy to adjust, great if you want to run logging/monitoring software on the same PC.
    • Cons: Requires that PC to stay on, Windows updates can occasionally ruin your day, and it is software licensing rather than a one‑time hardware brick.

  3. Hybrid hacky route

    • Tiny single board computer (like a Pi clone with a proper RS‑232 hat) plus socat or ser2net.
    • Cool if you like tinkering and want full control, not cool if you want something the boss will not yell at you about when it goes down at 3am.

If your priority is reliability in an industrial-ish setting, I’d lean to a decent hardware serial device server from Lantronix or Moxa.
If your priority is ease of remote access from multiple PCs and apps, or you already have a nearby PC, a software tool like Serial to Ethernet Connector is honestly simpler, especially for Windows apps that refuse to talk to anything that is not a COM port.

Given you said “remote access and monitoring” and you sound a bit lost in the hardware jungle, I’d probably start with a USB to RS‑232 adapter into a spare PC and test with a Serial to Ethernet Connector style app first. If it does what you want, then decide if you want to replace the PC with a dedicated hardware box later.

Need a serial to Ethernet connector recommendation
Need a serial to Ethernet connector recommendation1536×636 151 KB

3

If you just want “reliable and boring” rather than a science project, I’d look at this a bit differently than @espritlibre did.

First thing to decide: what exactly do you need from the network side?

  • Do you need multiple people/apps to connect at once?
  • Is the serial device half‑duplex or very timing sensitive?
  • Do you control the software talking to it, or is it some ancient Windows app that only knows COM1–COM4?

That changes the answer more than people admit.

1. When dedicated hardware is not the best first step

I know dedicated serial device servers sound like the obvious pick, and they’re solid, but they also love to surprise you with:

  • TCP vs UDP vs “virtual COM” weirdness
  • Annoying web UIs from 2005
  • Licensing or proprietary config tools that only run on old OS versions

If you’re still figuring out how the protocol behaves, throwing a hardware box in first can make debugging way uglier than it needs to be.

In that sense I partly disagree with the “start with hardware” vibe. I usually prototype in software first, then decide if I really need a dedicated brick.

2. Software approach that actually behaves like a local COM port

If the device is near a Windows PC and you can keep that PC on, a software bridge is honestly the least painful way to understand what’s going on and see if your use case even works over the network.

This is where something like Serial to Ethernet Connector shines:

  • It exposes your physical RS 232 port over the network.
  • On another machine, it creates a virtual COM port that behaves like the real thing.
  • Your old app never knows it is talking over TCP/IP.

It is not just “this app that shares serial ports.” It is more like a full serial over IP platform that gives you:

  • Point to point or many to one connectivity
  • Encryption and access control for industrial or lab environments
  • Support for multiple COM ports and simultaneous clients
  • A pretty sane UI to map and manage ports

You can grab it from here to test it in your setup:
download powerful Serial to Ethernet tools for Windows

If your workflow is basically “old Windows software talks to COM port forever,” Serial to Ethernet Connector tends to just work, without forcing you into raw TCP socket programming or messing with odd drivers from random converter vendors.

3. When to move to a hardware box

Once you confirm everything works fine over the network with Serial to Ethernet Connector, then ask:

  • Do I really need a 24/7 headless solution with no Windows updates in the way?
  • Is there any concern about the PC dying or being rebooted by someone?
  • Is your environment noisy / industrial / unconditioned?

If yes, then invest in a dedicated RS 232 to Ethernet device server like the ones @espritlibre mentioned. At that point you already know:

  • Required baud rate, flow control, and latency tolerance
  • Whether you need RFC2217 style virtual COM on the remote side
  • How many simultaneous connections you actually need

So you pick hardware that matches reality instead of guessing.

4. Stuff people forget to check before buying anything

Before you spend money, verify:

  1. Signal levels
    Is it really RS‑232 and not TTL serial? If it is TTL, you’ll need a level shifter before anything touches Ethernet.

  2. Handshake lines
    Some old gear absolutely depends on RTS/CTS or DTR/DSR. Make sure any solution you choose fully supports those lines.

  3. Idle connection behavior
    Some devices drop if the TCP connection blips for half a second. Test reconnection logic using the software bridge first.

  4. Firmware / long term support
    Cheap boxes are fine for hobby use, but in production I want something that still gets firmware updates and does not randomly corrupt its config after a power flicker.

If I were in your shoes and “a bit lost,” I’d:

  1. Use a decent USB to RS‑232 adapter on a nearby Windows PC.
  2. Install Serial to Ethernet Connector from the link above.
  3. Prove the concept with your real software and real traffic.
  4. If it runs clean for a while, decide whether the PC stays, or you replace it with a hardware device server later.

That way you do not marry some random RJ45 brick only to figure out it does not play nice with your ancient serial protocol.

5 Likes
4

If you want a slightly different angle than what @waldgeist and @espritlibre already covered, think in terms of lifecycle rather than just “which box/software do I buy.”

1. Clarify how “remote” you really mean

Before choosing hardware vs software, decide:

  • Is this only inside one LAN/VPN, or across the public internet?
  • Do you need access from SCADA/PLC, or just one or two Windows apps?
  • Is this a one‑off device or the first of many identical installs?

If it is strictly LAN and single‑app, almost any RS‑232 device server works. If you expect future duplication, centralized management and licensing suddenly matter a lot.

2. Where Serial to Ethernet Connector actually fits

Using Serial to Ethernet Connector is not just “PC-in-the-middle instead of a hardware box.” It covers a slightly different set of problems:

Pros

  • Very transparent for stubborn Windows software that insists on a local COM port.
  • Supports multiple virtual COM ports and more complex topologies like many-to-one or one-to-many.
  • Encryption and access control built in, which is underrated if you are crossing subnets or using a shared corporate network.
  • Fast to reconfigure when you are still figuring out baud rates, parity, or who should be able to connect.

Cons

  • You inherit all the fragility of a general-purpose OS: Windows updates, antivirus, user logins, and surprise reboots.
  • Depends on USB to RS‑232 hardware quality, which introduces another failure vector.
  • Licensing cost scales with port count and number of hosts, so long term it might be pricier than a simple device server.
  • Not ideal for harsh industrial environments or where IT refuses to keep a local PC in a panel or cabinet.

My rule of thumb:
Use Serial to Ethernet Connector when you care more about “the old Windows application must not change” than about “this must survive five years in a dirty cabinet.”

3. Where I slightly disagree with the others

  • @espritlibre is right that USB + software is great to prove the concept. I would not leave that as the final production solution in a plant floor or unmanned site. People turn PCs off, IT patches them, someone plugs in a label printer and breaks your USB enumeration, etc.
  • @waldgeist is cautious about jumping straight to hardware device servers, but in many industrial setups I prefer the opposite: start lab tests on a device server similar to what you will deploy, so you actually test watchdog behavior, power loss, and reconnection characteristics in the same class of hardware you will ship.

For anything 24/7 and “hands off,” a decent device server from Moxa, Lantronix, or similar is still my long‑term choice, even if I temporarily use Serial to Ethernet Connector during the protocol exploration phase.

4. Concrete decision path

Given your “remote access and monitoring” requirement:

  1. In a lab or office setting

    • Use a USB‑to‑RS‑232 cable into a spare PC.
    • Install Serial to Ethernet Connector.
    • Confirm the legacy app behaves correctly over the virtual COM.
    • While testing, log timing, reconnection, and any framing errors.

  2. When moving to production

    • If the PC is under your tight control and in a safe environment, you can keep the software approach.
    • If the location is remote, dirty, or lightly supervised, migrate to a hardware RS‑232 to Ethernet unit and configure it to mimic the working Serial to Ethernet Connector setup (baud, parity, TCP mode, etc.).

  3. Plan for scale

    • More devices coming later: weigh Serial to Ethernet Connector licensing against several lower‑port hardware servers.
    • Need central monitoring: hardware with SNMP and log export may be simpler to integrate than cobbling monitoring around a Windows box.

5. Summary comparison in your context

  • Serial to Ethernet Connector

    • Best for: preserving legacy Windows workflows, flexible lab setups, quick testing, encryption without touching app code.
    • Weak for: harsh environments, sites where nobody babysits a PC, very cost‑sensitive large fleets.

  • Hardware device server (Moxa, Lantronix, etc.)

    • Best for: “wire it once and forget it,” panel or DIN‑rail mounting, low power, years of uptime.
    • Weak for: apps that hard‑require a COM port unless you add extra virtual COM software or RFC2217 drivers.

Use the software first to remove protocol uncertainty, then only lock in hardware once you know how your specific RS‑232 device behaves over the network.