3COM CORPORATION

VARMODEM 2400

Modem Type             Data (synchronous/asynchronous)
Maximum Data Rate      2400bps
Data Bus               8-bit ISA
Data Modulation        Bell 103A/212A
Protocol
                       ITU-T V.21, V.22, V.22bis, V.23

[Image]

                                CONNECTIONS

         Purpose           Location            Purpose           Location

  Line out                    CN1       Volume                     SW2

  Line in                     CN2

                  BASE I/O ADDRESS SELECTION

  Port                        J3                  J4

  » COM1: (3F8h)             Off           Pins 2 & 3 closed

  COM2: (2F8h)                On           Pins 2 & 3 closed

  COM3: (3E8h)               Off           Pins 1 & 2 closed

  COM4: (2E8h)                On           Pins 1 & 2 closed

           INTERRUPT SELECTION

  IRQ                         J5

  » 4                 Pins 1 & 2 closed

  3                   Pins 2 & 3 closed

              DTR SIGNAL

  Setting                SW1/1

  » On              DTR forced high

  Off                  DTR normal

                          RESULT CODES

  Setting                                    SW1/2

  » Off                           Verbal result codes enabled

  On                             Numeric result codes enabled

          RESULT CODES DISPLAY

  Setting                  SW1/3

  Off                Display disabled

  » On                Display enabled

            ECHO COMMANDS DISPLAY

  Setting                      SW1/4

  » Off                  Local echo enabled

  On                    Local echo disabled

                                AUTO ANSWER

  Setting                                            SW1/5

  » On                                Modem does not answer on first ring

  Off                                     Modem answers on first ring

           CARRIER DETECT

  Setting               SW1/6

  » Off               CD normal

  On               CD forced high

                 MULTI-LINE INSTALLATION

  Setting                               SW1/7

  » Off                         Single phone connected

  On                          Multiple phones connected

                      AT COMMAND SET

  Setting                               SW1/8

  » On                        AT command set recognized

  Off                          AT command set disabled

                                ESCAPE CODE

  Setting                                           SW1/9

  » On                                 Go to command mode and display OK
                                     result code when escape character is
                                                   received

  Off                                 Disconnect, go to command mode and
                                        display NO CARRIER when escape
                                            character is received

        VOLUME CONTROL

  Setting          SW1/10

  » Off         High volume

  On             Low volume

                         Proprietary AT Command Set

               See document V1254 for a full command summary.