H HEUER INSTRUMENTS - LM41 LM41 Datasheet (490kB)
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****No longer available****

The Level Meter LM41 is a handheld battery powered instrument for testing Voice Frequency transmission circuits and lines used for xDSL upto 200 kHz. The main characteristic of the LM41 is the large number of facilities provided in such a small package.

It combines the features of a comprehensive Level Meter (including Noise Meter, Return Loss, Impulsive Noise, Dropout Testing) with the fully Automatic Loss Measurement (ALM) function.

ALM is used in conjunction with the Responder R41 to automatically evaluate bi-directional loss and noise at both terminations of a transmission link.

Telephone conversation is supported via a plug-in handset. Ring voltage, loop voltage and loop current is measured and line activity is monitored by a speaker.

Great care has been taken to achieve easy operation of this instrument. All functions are activated by one button. Most instruments of this complexity revert to menu tree mode selection thereby necessitating handbook guidance or on screen help. The LM41 can be operated without these aids. Measurement results can be stored for later PC evaluation and printing.

The following features are provided:

  • 100 hours operation with dry cells
  • Battery voltage monitor
  • 200 kHz level meter (ITU-T O Supp 3.1)
  • Level recorder
  • Channel and Psophometric Filters (ITU-T O.41)
  • Automatic Loss Measurement (ALM)
  • Return loss measurement
  • Closed-box electronic calibration
  • (RLTU) Remote Line Testing
  • Impulse Noise Event Counter (ITU-T 0.71)
  • Simple Interruptions (ITU-T O.61)
  • Noise w/wo tone measurements*
  • Quantising Noise (ITU-T O.132) / SNR Measurements*
  • Oscillator
  • 600 W, TN12, 100 kW
  • Audio monitor
  • Line voltage, current and ringing
  • Telephone
  • Data storage
  • Opto-isolated PC-interface
*Only available with optional 1020 Hz Notch filter