The HP/Agilent 4937A Transmission Impairment Measurement Set (TIMS) is a portable field-service instrument for evaluating and maintaining telecommunication circuits. It delivers comprehensive voiceband transmission testing with integrated signaling capabilities, enabling accurate circuit performance assessment under various network conditions. The unit supports PBX system installation verification and broader network infrastructure maintenance through both AC and battery-powered operation.
Technical Specifications
Level and Frequency Measurement
• Frequency range: 20 Hz to 110 kHz
• Receiver level measurement: -60 dBm to +13 dBm
• Transmitter level measurement: -40 dBm to +13 dBm
• Transmitter output: -26 dBm to -2 dBm
• Transmitter resolution: 0.1 dB
• Accuracy at 1004 Hz: ±0.1 dB from -20 dBm to +13 dBm
Noise Characterization
• Measurement range: 0 to 99 dBrn
• Capabilities include noise-to-ground, signal-to-noise ratio, and three-level impulse noise assessment
Return Loss Testing
• 2-wire and 4-wire return loss measurement
• Singing return loss (low and high frequency modes)
• Peak-to-Average Ratio (P/AR) available as option
Signaling Functions
• E/M line seizure and holding for three line types
• Central office signaling simulation
• PBX network interface signaling simulation
– Key Features
• WECO 310 type transmit/receive connectors
• AC operation: 100, 120, 220, 240 Vac ±5%, 45–66 Hz
• Optional rechargeable battery pack with integrated charger (Option 001): >3 hours typical operation, 5 hours when fully charged
• Battery charging range: +5°C to +40°C; optimal range +5°C to +25°C
• Trickle charging during AC-powered standby
– Compatibility & Integration
Designed to IEEE 743-1984 North American measurement standards and current Bell standards. Transmitter spectra comply with IEEE standard P743 and Bell System Publication 41009.
