An apparatus for inhibiting data on a bi-directional bus includes a first portion having a first analog port and a digital output. A second portion has a second analog port and a digital input, and the digital output is operably coupled to the first digital input. The digital output of the first portion is configured to produce a digital representation of an analog input signal presented to the first analog port. Likewise, the second analog port of the second portion is configured to produce an analog output representation of a digital signal presented to the digital input. The first and second portion cooperate to inhibit the propagation of data presented to the second analog port as an input.