These amplifiers can be individually configured internally to either amplify or apply an offset to the chosen signal. Similarly, each amplifier can be configured (via internal jumper links) to take its input from any available signal line on the back plane, and place its output on any other signal line. Other settings allow a choice of gain ranges and signal inversion if required.  The most common configuration is to apply an offset to each of four photometry signals. If amplification is also needed, two amplifiers apply a sequential offset and amplification via a direct interconnection rather than via the system back plane.