Agilent/Keysight 37701A

The Agilent/Keysight 37701A is a digital data tester for installation, maintenance, and troubleshooting of T1, fractional T1, DDS, and datacom circuits. It delivers full transmit, receive, and through-path capabilities for comprehensive in-service and out-of-service testing across central offices, remote locations, and user premises. The unit integrates T1 and DDS testing with built-in CSU emulation and multiplexer/demultiplexer functionality, enabling technicians to validate circuit performance and insert test patterns into individual timeslots, subrates, and overhead channels before connecting user equipment.

Technical Specifications

• Bit-error rate (BER) testing - simple and full error analysis modes


• Signal level measurements on T1 circuits


• Error detection, analysis, and logging across all test patterns


• Frame slips measurement


• G.821 compliance testing with digital and analog measurements


• Time slot delay measurement


• Optional D4 jitter measurement


• Pulse shape, clock slips, and wander measurement (Option 001) Test Patterns:


• PRBS: 2^15, 2^20, 2^23


• T1/DS1 frame formats: D4, ESF, TIDM, SLC-96


• QRSS, 3 in 24, 8-bit word, loop, and control codes


• DDS stress patterns: TA55


• 256-byte user patterns (DSO only) Interfaces:


• DS0 A/B, DS1, DSIC


• RS-232-C, RS-449, V.35 (with optional datacom module supporting rates up to 1.544 Mb/s)


• HP-IB and RS-232 remote control

Key Features

• Built-in CSU emulation for pre-connection circuit verification


• Integrated multiplexer/demultiplexer for timeslot, subrate, and overhead insertion/extraction


• Monitor, through, and drop-insert modes for live-circuit analysis


• Auto-configuration capability


• Results storage and graphic presentation (Option 003)

Typical Applications

• T1 and fractional T1 circuit commissioning and maintenance


• DDS/Dataport service validation


• Datacom testing up to 1.544 Mb/s


• Signal integrity analysis in telecom networks

Compatibility & Integration The 37701A supports standard T1/DS1 interfaces across D4, ESF, TIDM, and SLC-96 frame formats. Optional datacom module integration (e.g., HP 15901A Option 002) extends capabilities to RS-232-C, RS-449, and V.35 interfaces.