Built-up of the TELINDUS CROCUS HDSL modem

Functions of buttons and LEDs can be found on the face:

• Power LED (PWR) - it indicates the switch-on state of the modem
• Test LED (142/TST) - it shows, that the modem operates in normal, or test operation mode. It has 4 different meanings:

  LED state	Explanation
  Doesn?t light	There is no any running test.
  Lights continuously	There is a running interface test, or a test started from the face.
  Blinking	There is a running test started by the control system.
  Flash	Control system stops the test started from the face.

• Error LED (ERR) - it lights in the case of error
• Transmit data LED (103/TDX) - it monitors the data sent by DTE towards the interface
• Synchronisation LED (SQ1; SQ2; SQ3) - It shows, if the modem is in synch in the given (first, second) pair of wire with the remote modem, and it indicates the quality of the data connection according to the issues mentioned below:

  LED state	On the proper wire pair...
  Green and blinking	there is an ongoing synchronization.
  Green	there is a data communication of good quality.
  Orange	there is a data communication of medium quality.
  Red	the connection is broken.

  (The third LED will never light, because the modems at our Department can handle only two wire pairs.)

• Receive data LED - monitors data given towards DTE by the data interface
• Switches
  • ET - Error Test (dual-loop)
  • AL - Analog Loop
  • RDL - Remote Digital Loop
  • DL - Digital Loop

  Rear panel of the modem is shown on the following figure:

  
  • PWR - power button
  • 230/115V - feeding connector socket
  • AUX - serial port, the modem can be connected to its control PC through this
  • G.703 interface - modem can be connected through this to the PCM trunk
    • Symmetric connection - RJ 45 jack
    • Asymmetric connection - coaxial sockets
    Pin positions of RJ-45 -> 2x RJ-11 connector converter:
    • green-yellow -> transmitting direction input (data signal to be forwarded from DTE)
    • red-black -> reception direction output (received data signal towards DTE)
  • Line connectors - connectors of the (copper) wire pairs connecting the modem with the remote modem. (Modems at our Department can handle only two wire pairs.)