Maximize the potential of PSTN network

The Maestro system, replacing the well known system Mirabel (precursor of maintenance systems PSTN), was designed to perform physical tests telephone lines and provide a simple diagnostic and localization of defects as well as qualifying these lines to support xDSL services. These tests can be launched by:

  • field technicians in charge of maintenance,
  • customer support in 7/24,
  • analysts in charge of preventive maintenance (by batch of test to analyse status of cables by example),
  • analysts in charge of marketing to promote/propose services only where they can be available (eligibility).

The system can easily:

  • be integrated inside IS to be able to:
    • get information regarding telephone lines in databases,
    • offer NBI to allow tests submission or retreive historic measurements,
  • use different exchanges (E10, EWSD...), DSLAM or MSAN.

The know-how of Vierling R&D teams during these last 25 years, has created:

  • an equipment to perform quickly, thousands of measurements per copper pair
  • a complex software and algorithms to:
    • generate a reliable diagnostic based on these measurements,
    • automatically detect elements on line (splitters, NID, phone sets, xDSL modems...).

Recently, Vierling Communication decides to offer all its know-how in this domain inside a portable solution which contains the same harware and clever algorithms as the Maestro system.

This equipment helps field technicians to do campaign measurements:

  • create eligibility database and help marketing to provide right services to right clients,
  • validate MSAN deployment before commissioning,
  • test unused pairs and provide a status for the whole cable.

Maestro system architecture and its integration inside IS

Principles - Sequence of a test

  • A test is launched by providing the sole phone number of the line (by example).
  • The server interrogates databases to identify on witch commutator (switch, DSLAM, matrix...) this line is related to.
  • The server pilotes the MTA (Metallic Test Access) function of the commutator to be able to establish a metallic link between the line and a test port of a MTDU.
  • The server identifies on which MTDU, the line has been returned.
  • MTDU performs all necessary measurements to establish a comprehensive diagnostic.
  • The server pilotes the MTA function of the commutator to release the line.
  • The server stores and displays value results and diagnostic to user.

ADMIN Station - Configuration management

Tests Web Application

After authentication and regarding the profile of the user:

  • On-demand tests
    • Run a line test and display results
    • Eligibility
    • MIB DSLAM Information
    • Internal information from commutator
    • Combined test (line + MIB)
    • Test xDSL plot and services
    • Historical results
  • Bulk tests
    • Lines selection according various criteria
    • Automatic (newly created lines, faulty lines…)
    • Periodically
    • Export results to backoffice treatments

Measurements and diagnostics provided by MTDU

Maintenance measurements

  • DC voltages: A/B, A/G and B/G
  • AC voltages: A/B, A/G, B/G, A/Bat. and B/Bat.
  • Resistances: A/B, A/G and B/G
  • Capacitances: A/B, A/G, B/G and EFF
  • DC currents: A/B, A/G and B/G
  • AC currents: A/B, A/G and B/G
  • Noise in vocal and xDSL bands
  • Fault location

xDSL eligibility measurements

  • TDR
  • Line Attenuation at 150kHz, 300kHz and 1MHz
  • Upstream and downstream ADSL and ADSL2+ rates

Line elements detected

  • Phone set, Fax, Modem (on/off)
  • RC socket, C socket or other NID
  • CO xDSL splitter
  • xDSL modem and/or splitter in client premise
  • Current limiter


  • Line Good in Test
  • Open 1 wire (A or B wire)
  • Open 2 wires
  • Unbalanced line
  • Insulation fault Ground (A or B wire)
  • Insulation fault between wires
  • Insulation fault between a wire and battery (A or B)
  • Multiple insulation faults
  • DC voltage presence (A or B wire)
  • DC voltage presence (between wires)
  • AC voltage presence (A or B wire)
  • AC voltage presence (between wires)
  • HR joint (A or B wire)
  • LF noise presence (voice band)
  • HF noise presence (xDSL band)
  • Balance fault in xDSL band