Vishay Intertechnology Inc., Malvern, Pa., makes optocouplers with input currents as low as 1 mA and photo-darlington transistor outputs. Coplanar lead frame construction ensures that the distance between the emitter and detector chips doesn't change with temperature, shock, or vibration. These devices are for signal transfer systems, loop monitor circuits, modems, and line cards. The devices come in single, dual, and quad-channel packages in 4, 8, or 16-pin plastic DIPs. K815P, 825P, 845P are UL rated for 5,000 Vrms for 1 min, while TCED1100, 2100, and 4100 are rated for 8,000 Vrms.