3COM CORPORATION

MICRO LINK 300

Card Type                Modem (asynchronous)
Chip Set                 U.S. Robotics
Maximum Data Rate        300bps
Data Bus                 External
Data Modulation Protocol Bell 103/113

                                                                      54163

                                CONNECTIONS

         Function            Label            Function             Label

  Line out/in - unidentified      CN1      DC power                 CN4

  Line in/out - unidentified      CN2      Power switch             SW1

  RS-232/422                      CN3      Analog loopback switch   SW2

                                  RS232C

        Setting           SW3/A        SW3/B        SW3/C        SW3/D

  Pin 2 receive/Pin 3       On          On           Off          Off
         send

    Pin 2 send/Pin 3       Off          Off          On           On
        receive

                             DIAGNOSTIC LED(S)

   LED      Color    Status                    Condition

    CD       Red       On               Carrier signal detected

    CD       Red      Off             Carrier signal not detected

    ON       Red       On                     Power is on

    ON       Red      Off                    Power is off

    AL       Red       On        Modem is in analog loopback test mode

    AL       Red      Off      Modem is not in analog loopback test mode

    SD       Red       On             Modem is transmitting data

    SD       Red      Off           Modem is not transmitting data

    RD       Red       On               Modem is receiving data

    RD       Red      Off             Modem is not receiving data

  MISCELLANEOUS TECHNICAL NOTES

  Note: Diagram not available.