The Keysight/Agilent/HP 44492A Reed Relay Multiplexer Card is a high-density switching module that expands the measurement capability of the 3457A Digital Multimeter. This plug-in card provides ten 2-wire reed relay channels with fast switching speeds and extended operational life, delivering up to 300 channels per second. Eight channels are software-reconfigurable for 4-wire resistance measurement, while two dedicated current channels support make-before-break switching up to 1.5 A and external device actuation. The card handles signals to 125 V peak (terminal-to-terminal or terminal-to-chassis) with minimal thermal drift of less than 3 µV, making it suitable for precision data acquisition in automated test systems.
## Technical Specifications
• **Channels:** Ten 2-wire reed relay channels; eight reconfigurable as four 4-wire ohm channels under software control
• **Current Channels:** Two channels rated for make-before-break switching up to 1.5 A
• **Maximum Voltage:** 125 V peak (terminal-to-terminal or terminal-to-chassis)
• **Thermal Offset:** Less than 3 µV
• **Closed Channel Resistance:** Less than 4 Ω at end of relay life
• **Switching Speed:** Maximum 300 channels per second
• **Frequency Range:** AC voltage and frequency operations specified to 100 kHz
• **Supported Signal Types:** DC voltage, AC voltage, AC+DC voltage, 2-wire ohms, 4-wire ohms, frequency, period
• **Dimensions:** 76 mm (3 inches) additional depth required for wiring
• **Weight:** 5.05 kg net (9.3 kg shipping)
## Key Features
• Reed relay construction for reliable, repeatable switching in demanding environments
• Low thermal offset minimizes measurement error in precision applications
• Flexible channel configuration supports both 2-wire and 4-wire resistance measurement modes
• Make-before-break switching on current channels prevents signal interruption during switching transitions
• Software-controlled channel routing streamlines complex switching sequences
## Typical Applications
• Automated test systems requiring high-speed multi-channel switching
• Data acquisition networks for DC and AC voltage measurement
• Multi-channel resistance and ohms measurement
• Frequency and period measurement across multiple signal paths
• Current switching and external device control in test environments
## Compatibility & Integration
Designed as a direct plug-in module for the Keysight/Agilent/HP 3457A Digital Multimeter. Compatible with HP 44492A-CONN Screw Terminal Connector and Relay Multiplexer Adapter.
