When using a Digital Control Unit (DCU) with LabQuest, automatic identification of sensors is disabled for the port used by the DCU. This is because the line used for auto ID of a sensor is the same line used for digital output. Once digital output has been enabled on a digital port (DIG 1 or DIG 2), that port will not be able to detect the removal of the DCU or the addition of any other digital sensor.

To turn off the digital output and enable auto ID, tap File > New.

Support for DCU with LabQuest is available in LabQuest App v2.7 and newer.

LabQuest 3 (LABQ3)
LabQuest 2 (LABQ2)
Digital Control Unit (DCU-BTD)