3COM CORPORATION

US ROBOTICS 1200

Modem Type             Data (synchronous/asynchronous)
Maximum Data Rate      1200bps
Data Bus               External
Data Modulation        Bell 103A/212A
Protocol

[Image]

                                CONNECTIONS

         Purpose             Location          Purpose           Location

  Line out                     CN1       Power                     CN4

  Line in                      CN2       Volume                    SW3

  RS-232/422                   CN3       Power                     SW2

                             DIAGNOSTIC LED(S)

    LED       Color        Status                  Condition

   LED1        Red           On         Analog loopback self test mode

   LED1       Green          On                    Data mode

   LED2        Red        Blinking      Modem is transmitting/receiving
                                                     data

   LED2       Green          On             Carrier signal detected

              DTR SIGNAL

  Setting                SW1/1

  » On              DTR forced high

  Off                  DTR normal

                            RESULT CODES

  Setting                                       SW1/2

  » Verbose result codes enabled                 On

  Numeric result codes enabled                   Off

           RESULT CODES DISPLAY

  Setting                   SW1/3

  » Display enabled           On

  Display disabled           Off

             ECHO COMMANDS DISPLAY

  Setting                        SW1/4

  » Local echo enabled            Off

  Local echo disabled             On

                                AUTO ANSWER

  Setting                                             SW1/5

  » Modem doe not answer on first                      On
  ring

  Modem answers on first ring                          Off

           CARRIER DETECT

  Setting               SW1/6

  » CD normal            Off

  CD forced high         On

                  MULT-LINE INSTALLATION

  Setting                               SW1/7

  » Single phone connected               Off

  Multiple phones connected               On

                        AT COMMAND SET

  Setting                                  SW1/8

  » AT command set recognized                On

  AT command set disabled                   Off

                         Proprietary AT Command Set

                         ANALOG LOOPBACK SELF TEST

  Type:          Register

  Format:        AT [cmds] S16=n [cmds]

  Example:       ATS16=139<CR>

  Description:   Selects the tone dialing test

  Command                                Function

       0         Data mode.

       1         Analog loopback.