Additional Features: Multiplexer, matrix, and I/O cards Relay closures automatically counted and stored in each card's onboard memory Unlimited contact life with solid-state relay (Model 3724) Automatic CJC for temperature measurements when used with screw terminal accessory (Models 3720, 3721, 3724) Optional Plug-In Cards: Model 3720 Dual 1x30 Multiplexer Card (auto CJC with 3720-ST) Model 3721 Dual 1x20 Multiplexer Card (auto CJC with 3721-ST) Model 3722 Dual 1x48, High Density, Multiplexer Card Model 3723 Dual 1x30, High Speed, Reed Relay Multiplexer Card Model 3724 Dual 1x30 FET Multiplexer Card (60 differential channels, automatic CJC with 3724-ST accessory) Model 3730 6x16, High Density, Matrix Card Model 3731 6x16 High Speed, Reed Relay, Matrix Card Model 3732 Quad 4x28, Ultra-High Density, Reed Relay Matrix Card Model 3740 32-channel Isolated Switch Card Model 3750 Multifunction Control Card (40 digital I/O bits, 2 analog output channels, and 4 counters) The Keithley 3706 offers scalable, instrument grade switching and multi-channel measurement solutions that are optimized for automated testing of electronic products and components. The Keithley 3706 system switch with high performance digital multimeter (DMM) contains six slots for plug-in cards in a compact 2U high (3.5 inches/89mm) enclosure that easily accommodates the needs of medium to high channel count applications. When fully loaded, a mainframe can support up to 576 two-wire multiplexer channels for unrivaled density and economical per channel costs. The high performance multimeter provides a tightly integrated switch and measurement system that meets the demanding application requirements in a functional test system or provides the flexibility needed in stand-alone data acquisition and measurement applications.