It looks pretty much identical to a Farallon EtherMac iPrint LT, but it's white and Apple branded (presumably it also has a Din-8 on the end not an RJ11 jack?) - The Farallon box is just a Localtalk to EtherTalk bridge, and therefore supports connecting to a LocalTalk network, despite being branded for printers.
I'd try connecting it to your Mac and seeing if it bridges the networks. From memory these can't pass TCP/IP, so you need something on the Ethernet side to to TCP/IP to AppleTalk/EtherTalk bridging to make that work on the LocalTalk side.
Edit: Actually it looks like it's a clone of the Farallon EtherMac iPrint SL...
https://indexarticles.com/business/business-wire/farallon-announces-ethermac-iprint-adapter-sl--the-first-and-only-imac-connectivity-solution-for-serial-stylewriters/