SPORTSTER 14,400
                            APPENDIX E.  FAX AND OTHER OPERATIONS
                                                                 

FAX OPERATIONS

Fax Modem Guidelines

      Using your fax modem for facsimile
      operations requires compatible facsimile
      application software.
      You can use the following command format
      to switch between fax mode and data
      mode.  (Use as you would a standard AT
      command.)
             AT+FCLASS=n
      The valid n values are 0 and 1.  Use n =
      0 (AT+FCLASS=0)
      to switch the fax modem to data mode.
      Use n = 1 (AT+FCLASS=1) to switch the
      fax modem to fax mode.
      To determine which mode the fax modem is
      currently in, use the following command.
             AT+FCLASS?
      The modem will return a value of 0 to
      indicate data mode or 1 to indicate fax
      mode.
      NOTE:  Whenever the fax modem is reset
      by using the ATZ command, by toggling
      the DTR signal, or by turning the power
      off and on, the modem will be set to
      data mode.
A Note to Programmers

      If you want to know more about the
      supported fax commands, refer to the
      standard for the Service Class 1 fax
      protocol.
         ANSI/EIA/TIA-578-1990 (EIA-578)
         Asynchronous Facsimile DCE Control
         Standard
         November, 1990  Approved:  October
         22, 1990
      You can obtain a copy of this standard
      by contacting Global Engineering
      Documents, at 1-800-854-7179.
HIGH SPEED/LOW SPEED PROTOCOL

Overview

      This section explains how an answering
      Sportster 14,400 modem switches its
      connection rate to match the rate of a
      calling modem.  It may be of help to
      those who want to try programming their
      computers to switch rates to match the
      Sportster 14,400's connection rate.  The
      material here applies only when the
      modem is set for variable rates at both
      the serial port and connection inter
      faces, &B0 and &N0, respectively.
      In both Originate and Answer modes, if
      the connection rate is set to &N0, the
      Sportster 14,400 negotiates with the
      remote modem to connect at the highest
      possible rate.  In addition, if the
      modem is set to Extended or Advanced
      result codes (X1 or higher) it signals
      the computer with one of the following
      result codes or the optional error-
      control (ARQ) result codes selected with
      the &An command.
                CONNECT   (300 bps)
                CONNECT 1200   (1200 bps)
                CONNECT 2400   (2400 bps)
                CONNECT 4800   (4800 bps)
                CONNECT 7200   (7200 bps)
                CONNECT 9600   (9600 bps)
                CONNECT 12000  (12,000 bps)
                CONNECT 14400  (14,400 bps)
      The modem sends the result code at its
      previous rate.  Then it switches to the
      new connection rate.
      If your software doesn't switch rates
      and you want to program it to do so, use
      the example on the next page as a guide.
      It demonstrates the occurrence of the
      CONNECT codes in the connection
      sequence, so that recognition of the
      codes can be used to switch the
      software.  The example uses a sequence
      of incoming calls, but the codes also
      apply to Originate mode connections as
      long as the modem dials out at a rate
      higher than or equal to the remote
      modem's rate.
      The example below assumes the following
      settings.
      Software:   Initially 19.2K or 38.4K
              bps, allowing the following
              range of connection rates:
              14.4K/12K/9600/7200/4800/2400/12
              00/300 bps
      Modem: X1 or higher (rate-specific
              CONNECT codes), &B0 (variable
              serial port rate), &N0 (variable
              connection rate)
Example

                           ModemSerial Port
      Action               Response    Rate
      1.Power on.
      19,200
      2.300-bps call comes in.         RING
      19,200
                           CONNECT   19,200
      3.Data link is established.
      300
        Data transfer takes place.
      4.Data session is over.    NO CARRIER
      300
        Call is ended; loss of
        carrier.
      5.2400-bps call comes in.        RING
      300
                                    CONNECT
      2400                 300
      6.Data link is established.
      2400
        Data transfer takes place.
      7.Data session is over.    NO CARRIER
      2400
        Call is ended; loss of
        carrier.
      8.14,4K-bps call comes in.       RING
      2400
                           CONNECT 144002400
      9.Data link is established.
      19,200
        Data transfer takes place.
      10.                  Data session is
      over.                NO CARRIER19,200
        Call is ended; loss of
        carrier.
Explanation

      1.The modem is powered on and is
         operating at 19.2K bps or higher, so
         that it is able to connect at 14.4K
         bps as well as at lower rates.
      2.A 300-bps modem calls.  The Sportster
         14,400 senses the incoming signal and
         sends the messages RING and CONNECT
         to the computer.  These messages are
         sent at 19.2K bps, the current serial
         port rate.
      3.Since the Sportster 14,400 responds
         CONNECT, rather than with a rate
         indicator, the software switches to
         300 bps.  The modem automatically
         shifts to 300 bps to accept the data
         from the incoming call.
      4.The 300-bps data session is
         terminated; the modem sends the
         computer the message NO CARRIER at
         300 bps.
      5.A 2400-bps call comes in.  The modem
         responds RING and CONNECT 2400.
         These message are sent at the current
         bit rate of 300 bps.
      6.The software, receiving the CONNECT
         2400 message, adjusts accordingly to
         the higher bit rate.  The modem also
         shifts to 2400 bps.
      7.The 2400-bps data session is
         terminated; the modem sends the
         computer the message NO CARRIER at
         2400 bps.
      8.A 14,400-bps call comes in.  The
         modem responds RING and CONNECT
         14400.  These messages are sent to
         the computer at the current bit rate
         of 2400 bps.
      9.The software, detecting the CONNECT
         14400 message, adjusts accordingly to
         the higher bit rate.  The modem also
         shifts to 14,400 bps.
      10.    The 14,400-bps data session is
         terminated; the modem sends the
         message NO CARRIER at 14,400 bps.
      Keep in mind that whether or not your
      computer adjusts to these rate changes,
      the Sportster 14,400 automatically
      shifts connection rates if it is set to
      &N0.
VOICE/DATA COMMUNICATIONS

      When you install the Sportster 14,400,
      you have the option of plugging your
      phone into the second modular jack of
      the modem so it's available for voice
      calls.  You can also use the phone to
      set up communications with another user
      whose modem uses the AT command set,
      such as a USRobotics or USRobotics-com-
      patible modem.
      
Preparation

      First call the other user to establish
      the parity, word length and number of
      Stop bits the other person's modem ac
      cepts.  Then turn the call over to your
      modems, as follows.
      
Procedures

      1.Without hanging up the phone, have
         your modem go off hook in Originate
         mode.  Type the following command.
             ATD <Enter>
         NOTE:  Be sure the modem is not set
         to X2 or X4, or it will return the NO
         DIAL TONE result code and hang up.
      2.The other party should have the
         remote modem go off hook in Answer
         mode.  The following command is used
         to do this.
             ATA <Enter>
      3.Now both of you can hang up your
         respective phones while the two
         modems establish the data link.  They
         will maintain the link until one of
         you gives your modem a command to
         disconnect.
         Either party's device can be the
         originate or answer modem; it doesn't
         matter who made the phone call.  But
         one modem must enter Originate mode
         and the other then enter Answer mode.
         You and the other party, therefore,
         must agree on which command, ATD or
         ATA, you will each use.
         

