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I'm using the 620 WinLoader software that ties to an ancient Honeywell LM 620-25/35.

And I've gotten it to work in a one-to-one connection with an RS422 USB adapter. (After lots of rewiring cables.)

Now the tricky part. I've got a coworker who wants to remote into a single box and control 8 LMs (one at a time).

The 620 WinLoader software will only recognize COM1 or COM2.

I figured "No worries!" I'll just use hub4com from the com0com project and tie the COM lines (again, one at a time) to a virtual COM 1. Nope. hub4com won't do it the way Honeywell wants it to. Swell.

I can get an RS422 switch for $600. I'd rather not.

Some thoughts I've had is renaming the COM port via a program. It can be done in Control Panel, but my coworker is going to run into snafus doing that over and over.

I wanted to write a program to do this automatically. However, according to a Microsoft forum, I've found this is not something the average programmer really wants to deal with. facepalm Fabulous. (Note that I'm still considering it.)
I've also found this page by FTDI: http://www.ftdichip.com/Support/Utilities.htm . This might be user friendly enough. I'll ask him when he gets back in town.

Help me, DaniWeb-Kenobi! You're my only hope!

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Dani AI

Generated

— short, practical roadmap and things to try next.

If WinLoader truly insists on “COM1 or COM2”, there are three workable families of solutions: (A) a hardware switch so only one physical adapter is present as COM1 at a time, (B) reassign the Windows COM numbering so a chosen adapter becomes COM1/COM2, or (C) create a virtual COM1/COM2 that redirects to whatever real port you need. Each has trade-offs; hub4com is useful but known to be flaky when mixing physical ports and virtual hubs (it often won’t behave the same way as a single real COM device). (sourceforge.net)

Quick troubleshooting first: use Process Monitor (Procmon) to watch what WinLoader opens (filter for CreateFile on \.\COM*). That tells you whether the program expects a raw device path, specific modem control lines, or hardware that identifies itself a particular way. Procmon is the fastest way to confirm what “Honeywell wants”. (learn.microsoft.com)

If you want the cheapest reliable hardware route, a manual USB switch (or a small USB hub + a single USB↔RS422 adapter you physically connect to the selected LM) is simple: only the active adapter will be present and can be assigned COM1. To make COM1 available you may need to remove stale/hidden COM assignments first (Device Manager → View → Show hidden devices) or clear the ComDB bitmap in the registry — back up the registry before editing. Digi’s KB and other docs explain the ComDB/COM Name Arbiter cleanup. (digi.com)

Software options: if you use FTDI-based adapters, FTDI’s app note shows how to reassign PortName entries and adjust the ComDB so you can script a deterministic COM number for a device (requires admin and care). Alternatively a commercial serial‑to‑Ethernet / virtual‑COM product can create a local COM1 mapped to any remote/real serial line and run as a service so WinLoader sees COM1 before login (examples: FTDI app notes and commercial redirectors). (ftdichip.com)

If you elect to automate renaming, the basic registry change looks like:

# run as admin (example — replace with the device’s actual registry path)
Set-ItemProperty "HKLM:\SYSTEM\CurrentControlSet\Enum\<DeviceInstance>\Device Parameters" -Name PortName -Value "COM1"

After changing PortName you’ll usually need to free/repair ComDB or restart the device (DevCon can disable/enable without full reboot). For a managed, service-based approach that lets non-admin users switch ports safely, look at utilities like ComPortMan. Always backup the registry and test on a spare machine first. (powershellgallery.com)

Suggested next steps: 1) run Procmon while starting WinLoader to see exactly what it looks for; 2) try the simple USB switch approach to verify the app works when a single physical adapter is presented as COM1; 3) if that works, either script the FTDI/registry assignment (FTDI AN_132) or move to a commercial redirector so your coworker can select the LM without manual Device Manager work. (learn.microsoft.com)

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