AirTalk is a dongle that extends a LocalTalk (or PhoneNet, or equivalent) network over WiFi.

The AirTalk has a serial port, where you can either plug in a modem cable to a single LocalTalk device (Mac, printer, router, etc) or plug a LocalTalk or PhoneNet box in to add it to the end of a whole LocalTalk network. It can either get its power from Micro USB or from an ADB passthrough.

AirTalk is intended to be user friendly and plug and play. It requires no software on your vintage Mac or LocalTalk device to use it, the Chooser extension only sets it up, so it will work with things like printers or routers as well as with Macs.