I’m trying to connect to a device using an RS232 serial port in my virtual machine, but I can’t get the VM to recognize the port. Has anyone set this up successfully before? I need this for a legacy application and would really appreciate some advice or steps to follow.
I’ve got this home lab running Hyper-V – nothing too wild, just your bog-standard mix of VMs doing their thing. The catch? Some of my legacy comm gear is old-school, strictly serial. Like, it’s straight outta a movie where folks wear baggy jeans and slam phones shut.
At first, I tried to make do by chaining USB-to-serial converters all over my workspace. It looked like a spaghetti accident on my desk, and honestly, it was about as reliable as a dial-up modem during a thunderstorm. I got tired of fumbling with cables and adapters whenever I needed to bridge a VM to one of those ports. Then, late one night (after too much coffee), I stumbled on something called Serial to Ethernet Connector.
I set it up, mapped my local serial port over the network, and within a few steps, my virtualized Windows machine started talking to real-world devices.
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Install Serial to Ethernet Connector
Download it and let it do its thing (no arcane runes or registry spells required). -
Share Your Serial Port
Choose which comm device to share – for me, it was COM1 on the host. -
Access on the VM
Fire up SEC inside your VM, connect via TCP/IP to the host, and boom! Serial port right in your Hyper-V session.
Frankly, there are fancier, more elaborate ways to connect serial ports to VMs. (Paravirtualized solutions, hardware PCI passthrough, such-and-such.) But if you’re in a hurry, or just want something simple without cobbling together scripts and crossing your fingers after each Windows update, this works.
If your Hyper-V box needs to chat with a serial gadget, Serial to Ethernet Connector makes it a breeze. My advice: try the demo before shelling out the cash – but I was plenty surprised by how well it fit into my convoluted setup. If anyone else has battled this annoyance, drop your workaround below – always keen to compare battle scars.
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I saw Serial to Ethernet Connector, and yeah, it’s a slick workaround when you can’t get native passthrough, but honestly, I’m not sure that’s always the best approach.
Have you messed around with native passthrough options at all? In VMware Workstation and VMware ESXi you can configure your VM to map to a physical serial port on the host (like COM1) under the VM’s hardware settings. Hyper-V basically ignores serial ports (classic MSFT), but some folks have luck with PCIe serial cards + Device Guard passthrough. That’s pricey and a pain but worth a shot if latency is a dealbreaker.
If you’re curious about more in-depth setups and tricks with RS232 ports in virtual machines, you could check out making virtual machines talk to real COM ports for some further info and features. Sometimes you gotta mix multiple hacks to make it work!
So: try native passthrough if your hypervisor allows, USB assignment if it doesn’t hate you, and then stuff like Serial to Ethernet Connector if you just need it functional and can deal with a bit of “network hop” jankiness. Hope your legacy device appreciates the effort – mine keep threatening to unionize whenever I try new solutions.
If you’re still wrestling with RS232 in virtual machines, here’s another angle – and I’ll go out on a limb and say I’m not convinced by all the “serial over Ethernet fixes everything” love, though kudos to @mikeappsreviewer and @voyageurdubois for their thorough breakdowns and creative solutions. (Honestly, every time I see someone recommend another USB-to-serial dongle, my drawer of failed adapters shudders.)
Here’s my 2 cents: One method that gets overlooked is using PCI/PCIe passthrough, especially if you’re running on a beefy workstation or server. Sure, it’s a bit more advanced and mostly available in something like ESXi or certain KVM/QEMU setups, but if your VM host has a real serial card installed, you can assign the whole device directly to the VM. No TCP/IP weirdness, no timing hiccups, just the raw metal between your legacy app and that stubborn hardware. Yes, it’s pricier and not every budget or rig supports it – but if you’re looking at true 1:1 compatibility, this is as close as you’ll get to physical.
If that’s not possible, I gotta admit, Serial to Ethernet Connector is stupidly convenient for spinning up a network-accessible serial port that your VM can grab, especially if you don’t need micron-level timing accuracy. It’s much better than most DIY scripts or open-source serial port redirectors I’ve seen – SEC is basically a professional-grade app for turning your local serial port into a networked resource that virtual machines recognize natively. That’s especially handy if you want to skip the whole “cable drag across the datacenter,” plus you get centralized management.
For anyone still unsure about the exact process, there’s a seriously detailed breakdown on achieving seamless RS232 connectivity in your virtual environment that’s worth a skim. Just don’t expect any solution to be perfect for super oddball industrial hardware – I still have devices that only work after three full moons and a sacrificial offering of deprecated COM drivers.
Final tip: if your legacy app is crashy, double check handshake settings (RTS/CTS, DTR/DSR) and try a different VM hypervisor if you have that option. Sometimes it’s not the port – it’s the emulator at fault. And for the love of all that is serial, never trust Windows to install the right drivers the first time.
Honestly, everyone’s got their war stories with RS232 in VMs. Reading takes on Hyper-V and the serial-over-IP tricks is like revisiting The NeverEnding Cable Swap Challenge. Here’s where I’ll pivot slightly: If you’re using VirtualBox or VMware (Workstation/ESXi), sometimes you can map the host COM port directly in the VM’s settings. It’s clunky but baked-in—no extra software, no “am I on the right subnet?” headaches. Just watch out for Windows permissions and conflicts—you might have to run both host and VM as admin, sometimes futz in Group Policy.
But from a reliability standpoint? That “Serial to Ethernet Connector” solution is slick, especially if you’re VM-hopping or want shared access. Pros: cross-platform support, less cable mess, and (in my setups) better uptime than anything DIY. Cons? Licensed, not cheap if you want lots of ports, and not always perfect for real-time, latency-sensitive gear (think CNC controllers choking on network hiccups). Also, it’s another thing to update.
Frankly, hard-pass on more USB dongles unless you want to build a monument to failed adapters. PCI/PCIe passthrough (hinted at by the other answers) is powerful, but only on certain hosts and not for everyone.
Don’t forget: On some Linux/KVM VM setups, socat or ser2net can do something similar, with a steeper learning curve but gratis.
TL;DR—if you want minimal hassle and don’t mind paying, Serial to Ethernet Connector is arguably your best bet. If you need real hardware-level performance (industrial apps!), pursue PCI/PCIe passthrough. Budget-conscious and like tinkering with config files? Try open-source like ser2net, but expect to lose a few evenings and maybe some hair.
Anyone else notice Hyper-V’s still got no plug-and-play for legacy ports? Time to send a courtesy fruit basket to the Microsoft dev team…