Piconet is a peripheral expansion system for Nimbus.

It allows up to 30 devices to be connected and controlled from one output port using a series of individually addressable modules. "Nimbus purchasers benefit from the fact that they do not pay for unwanted output capability but they can expand their system by one Piconet module at a time when required."

Each external device in use requires a separate Piconet module, although each module can be reconfigured at any time for different devices.
Either serial or parallel modules are available to suit printers, plotters bit pads, modems and similar devices.
Piconet relies on a series of interfaces; one in each of the modules required for a peripheral. The modules are connected in parallel electrically but are logically independent.

Each separate peripheral requires its own Piconet module for connection to the Nimbus through the auxiliary serial interface. The modules are connected in a daisy chain from the Aux socket on the Nimbus rear panel.
A Piconet module consists of a small plastic case about 190 x 110 x 30mm containing a board with the
interface circuitry.
Serial and parallel modules are available. You may fit one or more Piconet module boards inside the
computer unit if there are expansion slots available.

The power supply unit in Nimbus will allow from two to four additional Piconet modules to be interconnected with up to three metres between modules. Further modules will require an in-line power supply.
The exact number of modules which may be powered from the Nimbus power supply depends on the types of peripherals connected and on the length of cable being used.

A utility called PICONFIG, supplied on distribution disks with MS-DOS version 3.10 or later, enables you
to match your Piconet module to the particular devices to be connected. The configuration for the most
regularly-used device may be held in the module’s configuration memory, other configurations may be kept in a disk file. Alternatively, PICONFIG can be used to produce an immediate but temporary new
configuration on the module.
Once the Piconet module has been configured to suit a particular device, it can be accessed through the
operating system or from any high-level language able to access MS-DOS devices.

Piconet serial modules can take two forms: internal and external.
Internal modules fit into an expansion slot in the Nimbus case with internal connections and an external socket for the input/output device.

Here is the internal serial Piconet card.
This card also contains a Philips PCF8573P Real Time Clock with battery backup.
This was used with RMNET on the server to ensure that the network clock
was set each time the server was switched on:

External modules are housed in plastic cases and may be interlinked with up to 3m of cable. A 3m length of cable is supplied. The parallel module is only available as an external module.