An isolated data acquisition device including a plurality of data acquisition channels, an isolated system management unit coupled to the data acquisition channels, a host system management unit, a serial bus coupled to the host system management unit and the isolated system management unit, and isolation circuitry coupled to the serial bus. The isolation circuitry electrically isolates the host system management unit from the isolated system management unit and the data acquisition channels. During operation, the isolated system management unit and the host system management unit may each store data associated with one or more pending bus transactions. Each of the system management units may select at least one of the pending bus transactions according to a predetermined priority scheme, encode and serialize the data associated with the selected bus transaction, and transmit the serialized data across the isolation circuitry to the other system management unit via the serial bus.