Emulate USB drive in Linux for plugged-in USB devices

Drudge

7/31/24, 5:02 PM

I have a document management system and want to use my multi-function printer to directly scan into a directory in the Linux file system where my DMS can read from and processes the files automatically.

However, my multi-function printer is a bit older and only allows USB connections and I don't like it to always scan on a USB drive and re-plug it into my Linux machine afterwards.

Is there a possiblity to attach the printer to the Linux server, whereby the Linux server does not threat this device as a printer, but emulates a small USB drive for the multi-function printer, so my DMS can read from this emulated device after scanning documents? I currently use Debian 12, if relevant.

0 + 4

linux

debian

emulation

Nikita Kipriyanov

7/31/24, 5:10 PM

In the ServerFault the proper answer could only be "buy a new printer". However, consider that your printer expects a *USB device* but your Linux system currently is a *USB host*. Device/OTG mode is not something you expect to be implemented on a PC. Rather, it is usually implemented in smaller devices. What you are asking is impossible to implement "directly", as it will also require various hacks (e.g. filesystem needs to be emulated too, plug/unplug the "flash" for the printer, receive notifications somehow which human normally receives visually on the printer LCD, and so on).

tsc_chazz

7/31/24, 5:15 PM

There are devices I've seen, years ago, that will supposedly allow connecting two USB hosts together, but I suspect they are Windows-only even if you can still find them.

Nikita Kipriyanov

7/31/24, 5:20 PM

@tsc_chazz USB is strictly asymmetric protocol, peers are absolutely not equal, and e.g. downstream port of a USB hub (built into the motherboard) which drives physically accessible USB ports on a computer could not possibly work as an Device port. Devices you mention were two "USB devices" fused back-to-back together and having their Device ports facing outside, something like two USB-to-UARTs or USB-Ethernets, which renders them incapable to do anything else. There is nothing Windows-only in this and such things are still available (and easy to build yourself, by the way).

tsc_chazz

7/31/24, 5:35 PM

Fair enough. I didn't know whether those devices would model as back-to-back network or as a common data storage area, as I've never tried to use one.

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EN: Emulate USB drive in Linux for plugged-in USB devices

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