Also, a useful feature of these is that the connection can also go the other way, so you can telnet into it over your wireless network and access the serial port of a device for rebooting or OOB access.
Can this be used as is to connect to UART on something like a Raspberry Pi? Or would it require some modification to the connector? Or is this a totally different thing?
It always bugs me when I need to connect to a device via UART and I can ping the device, but need to be on or go through the “host” machine because the UART itself isn’t networked.
It’s a partially different thing. The connector is totally different, but the protocol is basically the same except the voltage. You’ll need a MAX232 / MAX3232 chip to translate between the two.
Of course, if your goal is using this to connect to the RPi console, you’ll have to modify the firmware quite extensively. Oops, no you won’t.