The dock input device supports units of FS (full-scale, or maximum input before clipping), and V (volts). The dock input channels support various engineering units, in addition to FS. One reason for including separate units and sensitivities, for the dock input device and the dock input channels, is to enable a voltage calibration at the device level, which then allows you to enter a standard sensitivity for a transducer connected to a particular input channel (e.g. 50 mV/Pa for a microphone or 100 mV/g for an accelerometer).
Both input channels use the same units.
The default voltage sensitivity of the dock input devices is 1.0 V/FS.