RAD DATA COMMUNICATIONS

MTM-20 (X.21, DC POWER)

Card Type       Modem (synchronous)
Chipset         Unidentified
Transfer Rate   32/64Kbps
Data Modulation QAM
Data Bus        Serial

[Image]

                                CONNECTIONS

        Function            Label            Function             Label

  DC power in                CN1       Analog loopback test        SW2
                                       switch

  X.21 serial port           CN2       Remote digital              SW3
                                       loopback test switch

  Line out (see pinout       SC1       Test pattern switch         SW4
  below)

  Local digital loopback     SW1
  test switch

            Note:Modem can be made to perform self-test by holding down
            SW2 and SW4. The DCD, TEST, and SQ LEDs should go on, and the
            RD LED should go off.

                                SC1 PINOUT

         Function           Terminal          Function           Terminal

  Ground                       1       Not used                     5

  Not used                     2       Transmit line                6

  Receive line                 3            Transmit line           7

  Receive line                 4

                        USER CONFIGURABLE SETTINGS

                  Setting                       Label        Position

  »   DCD forced high                            JP3         Pins 3 & 4
                                                              closed

      DCD normal                                 JP3         Pins 1 & 2
                                                              closed

  »   Signal ground connected to chassis         JP4         Pins 1 & 2
      ground                                                  closed

      Signal ground not connected to             JP4         Pins 2 & 3
      chassis ground                                          closed

  »   Line speed set to 64Kbps                   SW5        Position 4

      Line speed set to 32Kbps                   SW5        Position 3

                              TRANSMIT LEVEL

    Setting        JP5/A       JP5/B      JP5/C       JP5/D       JP5/E

  »     0dBm      Closed       Open        Open       Open        Open

       -3dBm       Open       Closed       Open       Open        Open

       -6dBm       Open        Open       Closed      Open        Open

       -9dBm       Open        Open        Open      Closed       Open

       -12dBm      Open        Open        Open       Open       Closed

                               CLOCK SOURCE

                Setting                                 JP1

  »               Internal                       Pins 1 & 2 closed

                  External                       Pins 3 & 4 closed

                  Received                       Pins 5 & 6 closed

                                LINE LENGTH

                  Setting                                JP2

  »                 0-10Km                        Pins 3 & 4 closed

                    7-13Km                        Pins 1 & 2 closed

       Auto select (not yet implemented)          Pins 5 & 6 closed

                             DIAGNOSTIC LED(S)

    LED         Color          Status                 Condition

    PWR         Green            On                  Power is on

    PWR         Green            Off                Power is off

    RTS         Yellow           On              RTS signal is high

    RTS         Yellow           Off              RTS signal is low

     TD         Yellow           On           DSU is transmitting SPACE

     TD         Yellow           Off           DSU is not transmitting

     TD         Yellow        Blinking        DSU is transmitting data

     RD         Yellow           On            DSU is receiving SPACE

     RD         Yellow           Off            DSU is not receiving

     RD         Yellow        Blinking          DSU is receiving data

    DCD         Yellow           On            Carrier signal detected

    DCD         Yellow           Off         Carrier signal not detected

    TEST         Red             On              DSU is in test mode

    TEST         Red             Off           DSU is not in test mode

     SQ         Yellow           On            Signal quality is good

     SQ         Yellow        Blinking        Signal quality is poor or
                                            test pattern contains errors