Keysight / Agilent / HP 44492A Reed Relay Multiplexer Card

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.