Agilent/Keysight 4937A

The Agilent/Keysight 4937A is a programmable Transmission Impairment Measuring Set (TIMS) engineered for voiceband transmission testing of telecommunications circuits and systems. This portable instrument delivers level, frequency, noise, return loss, and signaling measurements across the 20 Hz to 110 kHz band, with integrated E/M line seizure and hold capability plus central office and PBX signaling simulation at network interfaces.

Technical Specifications

Transmission Measurements

• Frequency range: 20 Hz to 110 kHz


• Level accuracy at 1004 Hz: ±0.1 dB from −20 to +13 dBm


• Transmitter level range: −26 dBm to −2 dBm with 0.1 dB resolution


• Talk isolation: >78 dB @ 4 kHz, decreasing 6 dB per octave above 4 kHz


• Noise modes: noise-to-ground, noise-with-tone, signal-to-noise, and three-level impulse noise


• Return loss: 2-wire and 4-wire measurements; singing return loss complies with IEEE P743 and Bell System Publication 41009


• Peak-to-average ratio (P/AR): Available as option Signaling

E/M line seizure and hold for three line types. Circuit indications include idle, seizure, and disconnect states via on-hook and off-hook conditions. Power
100, 120, 220, or 240 Vac (±5% −10%), 45–66 Hz. Optional battery pack (Option 001) provides over 3 hours operation with built-in charger. Physical
WECO 310 connectors for transmit/receive. Lightweight design for field service deployment.

Key Features

• Programmable control for automated test sequences


• Dual impedance support: standard 900 ohm or optional 150 ohm (Option 002)


• Standards alignment with IEEE 743-1984 North American measurement standard


• Seizes and holds three E/M line types simultaneously


• Simulates both CO and PBX signaling protocols

Typical Applications

• Voiceband circuit characterization and acceptance testing


• Transmission impairment analysis on 2-wire and 4-wire facilities


• E/M signaling verification at network interfaces


• Return loss and singing return loss qualification


• Noise performance assessment including impulse noise transients

Compatibility & Integration WECO 310 connectors enable integration with standard telecommunications test interfaces. Option 910 provides supplemental Operating and Service Manual. Calibration service available.