Agilent 3499A Switch Unit. Requires additional modules for your application. The Agilent 3499 family provides a high-speed, high-density electronic/optical switching solution for automatic test engineering (ATE) applications. It can scan at rates up to 350 channels per second, or open/close 200 channels in less than 0.1 second. The Agilent 3499A can accommodate up to five plug-in modules, routing up to 200 channels in a test system. The Agilent 3499B is a half-rack-width, 2-slot mainframe, allowing switching for up to 80 channels for ATE or desktop operations.