[jiehong]

Some audio/video receivers still use telnet to control them over the network, like those still sold by Denon/Marantz [0].

[0]: https://assets.denon.com/documentmaster/us/heos_cli_protocol...

[paradox460]

Lutron used it for their integrations platform up til very recently. It was extremely convenient, being able to write little scripts that do things like turn off all the lights

[w4der]

Some of KUKA's controllers still use telnet in their startup sequence.

[lambdaone]

A large industrial robot running an insecure protocol - what could possibly go wrong?