Agilent / Keysight 34923A 40/80 Channel Reed Multiplexer for 34980A

The Keysight 34923A is a 40/80-channel Reed Multiplexer module for the 34980A Multifunction Switch/Measure Unit mainframe. It delivers high-speed switching for automated test applications and data acquisition tasks, supporting flexible channel configurations: 40 two-wire channels, 80 one-wire channels, or mixed 2-wire and 4-wire arrangements on a single module. Reed relays enable scan rates up to 500 channels per second when connected to the mainframe's internal DMM.

Technical Specifications

• Channel Configuration: 40 two-wire, 80 one-wire, or mixed 2-wire and 4-wire on the same module


• Switching Speed: Up to 500 channels/second (with 34980A internal DMM)


• Relay Type: Non-latching reed switches organized in two equal banks


• Switching Voltage: ±150 V peak


• Switching Current: 0.5 A


• Carry Current: 1.5 A


• Input Protection: 100 Ω protection resistors on each relay


• Direct Current Measurement: Channels 41–44 only; external shunts required for all other channels


• Analog Bus Relays: Eight armature relays (four per bank) for Analog Bus connection


• Relay Counter: Built-in counter for maintenance planning

Key Features

• Flexible mixed-mode configurations support diverse test requirements


• Non-latching relay design with integrated input protection


• Standard 50-pin D-sub connectors compatible with existing infrastructure


• Optional terminal blocks available for 2-wire (34923T-001) and 1-wire (34923T-002) configurations


• Relay counter enables predictive maintenance scheduling

Typical Applications

• High-throughput automated test systems


• Multi-channel data acquisition and monitoring


• General-purpose scanning with rapid channel switching


• Current measurement via user-supplied external shunts

Compatibility & Integration Designed exclusively for the Keysight 34980A mainframe. Up to eight plug-in modules can be installed in a single mainframe. Multiple multiplexer modules connect to the built-in Analog Buses, enabling expanded scanning capacity across the system.