The Model 4999 from Endevco Corp., San Juan Capistrano, CA, is a low-pass filter signal conditioner with individual input ground isolation. The 16-channel, 2U, rack-mounted 4- or 6-pole low-pass filter conditioner supplies excitation current to IEPE-type sensors and remote charge converters. Broadband noise is specified at <30 µVrms, actual noise is <15 µV. Seven front panel selectable low-pass cutoff frequencies are configurable at the factory at time of order with standard frequency corners of 400, 800, 1600, 3200, 6400, 12,800, and 25,600 Hz ±2%. Gain is front-panel selectable of 1 or 10. The device accepts voltage type, IEPE, and PE remote charge converter inputs; an external calibration signal input is supplied.