Filiberto, Frank, Thomas This morning we tested the continuity and shined a flashlight on each of the PDs to get a response. PD forward voltage: Pin3&4: 0.415V Pin7&6: 0.418V Pin10&9: 0.417V Pin13&12: 0.417V We tested response of each PD: Pin3&4: 64mV to 270mv PD4 Pin7&6: 87mV to 320mV PD3 Pin10&9: 66mV to 220mV PD2 Pin13&12: 57mV to 240mV PD1 The PDs are not calibrated, and for their purposes, maybe they don't need to be but they work.