Dennis wrote:
It were me, I'd probably look into Bluetooth- or
Zigbee-based serial
extenders.
I'm not sure about Zigbee, but the useful range of Bluetooth is very
short. There are claims of over 30 meters, but as far as I can tell
that must be under laboratory conditions, e.g. in a faraday cage.
In the real world, more than about 3 meters line of sight works poorly,
as does non-line-of-sight at any distance.
Eric