PWA application as tcp/ip server

Is it possible to create small tcp/ip server in pwa application?
One devices used by us sends a wake up call to our POS software when device is activated.

As far as I know, this isn't possible.
For socket based communication, you would typically use web sockets.
Please see our FNC Chat apps that uses web sockets and where there is also a server app included.
Using web sockets, you could communicate to & from the PWA app to other devices also listening to the web socket server.
As an alternative, MQTT could also be possible as communication technique