
In early 1982 RM launched its 480Z Link system as a way of connecting multiple 380Zs together. 

With networking initially developed in-house, RM switched to Zilog's Z-Net when that company announced that it would be available to third-parties under licence, an easy switch given that RM's own networking system was already fairly similar. 

The 480Z main workstation was a Z80A machine with 32K running CP/NET but could be used as a stand-alone machine with the addition of a cassette for storage.

Meanwhile, The Z-Net system was being used by another British company to run a pioneering hotel room control system. 

Automatic Revenue Controls Limited of Watford had rigged up its Guest-key system at the Grosvenor House Hotel in London as an entire network with a micro in every room of the hotel, all linked to a central computer and which controlled the door locks and ensured that the lights were turned off when guests left the room. 

Keys, which used a sequence of notches along the edge, could be assigned to a particular room or act as a master key, all of which could be re-assigned should a key get lost.

