The HP/Agilent 4938A Network Circuit Access Test Set is a specialized instrument for testing and troubleshooting network circuits. It provides direct access to 4-wire simplexed leads and generates ringing signals for detailed circuit analysis. The unit delivers loop current and ringing voltage measurements essential for network access margin testing and is designed to integrate with the 4937A to form the complete 4937S Network Access Transmission Test Set.
## Technical Specifications
• Signal Generation: Ringing signal output
• Measurement Access: Loop current and ringing voltage
• Circuit Interface: 4-wire simplexed lead access
• Primary Function: Network circuit access and margin testing
## Key Features
• Direct access to 4-wire simplexed network leads
• Integrated ringing signal generation for circuit stimulation
• Dedicated measurement paths for loop current analysis
• Ringing voltage measurement capability
• Modular design for system integration
## Typical Applications
The 4938A serves telecommunications technicians performing network circuit access testing, loop current characterization, and margin validation on simplex circuit configurations. Field troubleshooting and laboratory analysis of network transmission circuits benefit from its specialized measurement access.
## Compatibility & Integration
The 4938A operates as a complementary unit to the 4937A, together forming the 4937S Network Access Transmission Test Set. This configuration expands testing scope across multiple circuit access parameters and measurement modalities. The instrument is optimized for telecommunication circuit testing environments.
Documentation including operating manuals and quick reference guides supports field deployment and maintenance.

















