The new PMT400 sub-system offers true photon counting using an end-on bialkali PMT tube with integrated high-voltage power supply and amplifier discriminator. This combined package increases reliability and decreases cost. The PMT400 is directly powered and controlled by the IonOptix model FSI700 Fluorescence System Interface under software control. PMT recording occurs at rates as high as 1000Hz through IonWizard and PMTACQ, our PMT module add-on. For stand-alone applications, a separate module is available that provides power and control voltage to the PMT400 and a BNC TTL count output for connection to other devices.