Agilent/Keysight 4935A

The Agilent/Keysight 4935A Transmission Impairment Measuring Set (TIMS) is a portable field instrument for testing transmission quality across voice and data circuits in telecommunication networks. It delivers a complete analog measurement suite to isolate faults and qualify circuits across multiple service classes. The 4935A operates within a 110 kHz bandwidth, enabling qualification of local loops for Digital Data Systems (DDS) up to 56 kbps.

It complies with Bell standards (BSTR 41009) and IEEE standards (IEEE 743-1984), making it suitable for North American network diagnostics.

Technical Specifications

• Frequency range: 20 Hz to 110 kHz with steps of 1 Hz, 10 Hz, 100 Hz, 1000 Hz, and 10,000 Hz


• Fixed frequencies: 404 Hz, 1004 Hz, 2804 Hz, 2713 Hz


• Four user-assignable frequency storage locations


• Output level: −40 dBm to +13 dBm, 0.1 dB resolution


• 3-level impulse noise generation at 1004 Hz or quiet terminated


• Optional Peak-to-Average Ratio (P/AR) signal: complex pulse train of 16 frequencies (140 Hz to 3890 Hz) at −40 dBm to 0 dBm, 1 dB resolution Receiver


• Input level range: −60 dBm to +13 dBm, 0.1 dB resolution


• Message circuit noise measurement: 0 to 100 dBrn (±1 dB from 10 to 100 dBrn; ±2 dB from 0 to 10 dBrn)


• Filter options: C-Message, 3 kHz flat, 15 kHz flat, program-selectable, 50 kBit, Psophometric (P.53), 275–3250 Hz flat, sound unweighted (J.16), sound weighted (J.16), 1010 Hz notch, 820 Hz notch

Key Features

• Cross talk isolation: >78 dB at 4 kHz, decreasing 6 dB per octave above 4 kHz


• Total harmonic distortion: >65 dB down from fundamental at 1004 Hz, 0 dBm (4 kHz filter)


• Selectable impedance: 600 ohm, 900 ohm, and bridged modes


• Circuit connection via 310 jacks


• Rugged portable design for field service deployment

Typical Applications

• Local loop qualification for voice and data services


• Transmission impairment diagnostics on carrier networks


• Pre-service circuit validation


• Field fault isolation and troubleshooting

Compatibility & Integration Complies with Bell standards (BSTR 41009) and IEEE standards (IEEE 743-1984) for North American telecommunications infrastructure.