The SamBus aka ‘The Card Cage’ was a multi-port expansion device to allow 4 expansion devices to attach to the CoupĂ©.

The SamBus also featured a battery-backed real-time clock (OKI M6242B) which MasterDOS and B-DOS could utilise for timestamping files.

All devices connected will use up some of the available power, and some will be more power-hungry than others. All future peripherals produced will carry a “Loading Factor” number which will be located near the device’s serial number and prefixed by the letters “LF”. This will allow you to estimate how much power a device is likely to consume. If the “Loading Factor” total is above 200 units for all the devices connected, an external 5v power supply will need to be plugged in to the SAMBUS via the external power connector.

The following peripherals were designed before the SAMBUS was in production, and you should assume the following “Loading Factor” units for them.

DeviceLoading Factor
External Drive Interface/Parallel Printer Interface15 LF units.
Parallel Printer/RS232 Comms Interface20 LF units.
The Voicebox15 LF units.
Sam Drive50 LF units each

PDF Manual Scan at

Apparantly SamCo never sold the additional power unit, although simple to adapt an existing unit to serve in it’s place.

After SamCo went under a number of similar units like the Two-up and Three-up appeared.

SAMBUS documentation + schematic

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