An apparatus includes analog-to-digital conversion (ADC) circuitry, digital processing logic, and digital-to-analog conversion (DAC) circuitry. The ADC circuitry is coupled to digitize multiple analog input signals so as to generate digital samples. The digital processing logic is configured to extract, from the digital samples, one or more first digital signals corresponding to a first selected subset of the analog input signals, and one or more second digital signals corresponding to a second selected subset of the analog input signals. The digital processing logic is further configured to output the one or more first digital signals to a digital medical instrument. The DAC circuitry is coupled to convert the one or more second digital signal into one or more analog output signals, and to output the one or more analog output signals to an analog medical instrument.
