It is possible to keylog via audio.

https://ieeexplore.ieee.org/abstract/document/10190721

It would take an especially perverse mind to keylog using audio on a KVM, though. The KVM basically has access to everything, any secondary spying using a microphone or a camera would provide very little added value.

	▲	saltcured 4 hours ago \| parent [-]
		Maybe it's for the super secret stuff that the datacenter emergency ops worker knows not to type through the KVM? ;-)

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BenjiWiebe 5 hours ago | parent | prev | next [-]

But the point of a device like this is that you (and your keyboard) are NOT physically present.

	▲	hinkley an hour ago \| parent [-]
		They mean the K in KVM could trivially have a keylogger. For the computers attached to that KVM. Audio is for logging for computers not attached to the device in question. Which could be up to and including a whole server room save a couple machines.

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ErroneousBosh 5 hours ago | parent | prev [-]

A long time ago (maybe in the mid-90s) I knew an elderly radio amateur who could not just "copy" CW by ear, but also RTTY. He could also pretty much tell what a teleprinter was printing just by listening to the noises it made, like he'd be facing away from it on the other side of the room reading out entire words from what was coming through.

Apparently in the 50s when he did his National Service he'd been in the Signals but "not in the regiment that's on his papers", make of that what you will.

I have noticed that with PSK modes and particularly PSK31 you can hear "CQ CQ CQ" as a distinctive pattern much in the same way as it is with CW.

IBM spent a fortune developing ATM keypads that - when correctly mounted - had keys that made the exact same noise no matter how you pressed them or how worn they were.

So I don't doubt that someone suitably clever could extract audio from a room and work out what was being typed.

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f1shy 5 hours ago | parent [-]

Do you have a pointer to learn more about the ATM keyboards? I would love to learn more about it

	▲	CamperBob2 12 minutes ago \| parent \| next [-]
		One really-cool way to solve that problem is to embed a 7-segment LED under each keycap. You walk up to the keypad and the 0-9 digits appear in random order. No one can shoulder-surf, look for wear or IR emission from the buttons, or train on the click sounds. Dell had those on every lab door in the building back in the early 90s. You felt like 007 every time you punched in your access code. I've never seen them anywhere since.
	▲	ErroneousBosh 4 hours ago \| parent \| prev [-]
		Maybe. They were necessarily very cagey about it back then, but I might have some documentation kicking about in storage. I tended to keep copies of every service manual I could get my hands on back then.