The Keysight/Agilent/HP 44474A is a 16-bit digital input/output module engineered for data acquisition and control system integration. It delivers flexible digital interfacing through 16 bidirectional data lines and 4 control/handshake lines, with reconfigurable byte-by-byte I/O architecture that supports independent 8-bit ports or a single 16-bit word configuration.
Technical Specifications
• Digital I/O Lines: 16 bidirectional lines with individual bit, dual 8-bit port, or 16-bit word addressing modes
• Control Lines: 4 dedicated control/handshake lines
• Input Logic: TTL compatible; Vin(high) ≥ 2.0 V; Vin(low) ≤ 0.8 V
• Output Stage: Open collector configuration
• Output Levels: Voh ≥ 2.4 V @ < 8 mA; Vol ≤ 0.4 V @ < 16 mA
• Current Sink Capability: 0.125 A maximum per I/O line
• Maximum Line Voltage: +30 V DC (line-to-chassis)
– Key Features
• Byte-level reconfigurability enables one 8-bit port for output while the other handles input simultaneously
• 0.125 A sink current per line permits relay and external load switching
• TTL-compatible input thresholds integrate readily with standard logic circuits
• Open collector outputs provide flexible pull-up implementations
• Individual bit addressing alongside port-level control options
– Typical Applications
• Relay and external device switching via open collector outputs
• Mixed-mode digital I/O operations requiring simultaneous input and output
• TTL-level sensor and control interfacing
• Industrial data acquisition and process control systems
– Compatibility & Integration
The 44474A integrates into Keysight/Agilent/HP 3499A, 3499B, and 3499C mainframes. It was also available as Option 014 for the HP 3488A Switch/Control Unit. External wiring connections typically employ a terminal block such as the HP 44484A.
