Agilent/Keysight 44474A

The Agilent/Keysight 44474A is a 16-bit digital input/output module for automated test systems and data acquisition applications. It provides 16 bidirectional data lines configured as TTL-compatible inputs and open-collector outputs, plus 4 dedicated control and handshaking lines. Each data line sinks up to 0.125 A, enabling direct control of external devices and relays. The module supports three addressing modes: individual bit access, dual 8-bit ports, or single 16-bit word operation. It plugs directly into Agilent 3499A/B/C mainframes and 3488A Switch/Control Units, integrating into existing test architectures.

– Technical Specifications

Digital Input/Output
• 16 bidirectional data lines
• Input compatibility: TTL (Vin High > 2.0 V, Vin Low < 0.8 V)
• Output type: Open collector
• Current sink: 0.125 A per line (Vout 2.4 V @ I < 8 mA; Vout Low < 0.4 V @ I 2.4 V @ I < 400 µA; Vout Low < 0.5 V @ I 2.0 V; Vin Low < 0.8 V
• Maximum line voltage: +5 V DC (line-to-chassis)

– Key Features

• Three independent addressing modes (bit, byte, or word)
• Screw terminal connection for field wiring
• TTL-level logic on all input lines
• Open-collector outputs for driving external logic and switching applications
• Sufficient current capacity for relay coil and solenoid control

– Typical Applications

• Contact closure detection
• External relay and solenoid switching
• Real-time digital signaling in test sequences
• Integrated control within automated measurement systems

– Compatibility & Integration

The 44474A inserts into Agilent 3499A/B/C Switch/Control Systems and 3488A Switch/Control Units (Option 014). The Keysight 44484A Terminal Block provides optional expanded connectivity.