
MULTI-TECH SYSTEMS, INC.

MT224AH

Modem Type                   Data (synchronous/asynchronous)
Maximum Data Rate            2400bps
Data Bus                     External
Data Modulation Protocol     Bell 103A/212A

                             ITU-T V.21, V.22, V.22bis, V.23
Error Correction/Compression MNP5, V.42, V.42bis

[Image]

                                CONNECTIONS

         Purpose             Location          Purpose           Location

  DC power                     CN1       Line in                   CN4

  RS-232/422                   CN2       Power switch              SW1

  Line out                     CN3       Volume                    R1

      ASYNCHRONOUS/SYNCHRONOUS

     Settings           SW5/D

   Synchronous            On

   Asynchronous         Off

                                AUTO-ANSWER

                 Settings                               SW4/E

   Enable auto answer/originate                          On

              Disable/answer                             Off

  Note: When SW5/B is set for Lease Line operation, the options on this
  switch change to Originate and Answer

             BLIND/WAIT DIALING

       Settings               SW5/C

  Wait for dial tone           On

   Blind dialing              Off

         BAUD RATE

   Settings        SW2

   1200bps     Position 1

    300bps     Position 2

   2400bps     Position 3

                   CD/DSR

       Settings               SW4/F

   CD/DSR normal              On

  CD/DSR forced high           Off

        COMMAND CHARACTERS

    Settings          SW4/D

   Echo enable         On

  Echo disable         Off

      COMMAND MODE

  Settings     SW4/H

  Disable       On

   Enable      Off

                   CTS

      Settings              SW5/A

   CTS forced high           On

     CTS normal              Off

                                CTS/RTS

              Settings                              JP2

   CTS follows RTS                          Pins 1 & 2 closed

  CTS forced high until disconnect           Pins 2 & 3 closed

                   DSR

      Settings               JP3

   DSR follows CD    Pins 2 & 3 closed

  DSR follows OH      Pins 1 & 2 closed

                FORCED DTR

      Settings              SW4/A

     DTR normal               On

   DTR forced high          Off

       JACK TYPE

  Settings     SW4/G

   RJ11        On

  RJ12/13       Off

       RESULT CODES

  Settings      SW4/B

   Verbose       On

    Terse        Off

      RESULT CODES

  Settings     SW4/C

  Disable       On

   Enable      Off

                    RTS

      Settings                JP1

   RTS forced high    Pins 1 & 2 closed

     RTS normal        Pins 2 & 3 closed

    SWITCHED/LEASE LINE

   Settings       SW5/B

   Switched       On

  Lease line       Off

      VOICE/DATA MODE

   Settings        SW3

    Answer     Position 1

  Originate    Position 2

                             DIAGNOSTIC LED(S)

    LED       Color         Status                  Condition

    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

    CD         Red            On             Carrier signal detected

    CD         Red            Off          Carrier signal not detected

    24         Red       Blinking fast     Modem connected at 2400bps in
                                                  reliable mode

    24         Red       Blinking slow    Modem connected at 2400bps with
                                                 data compression

    24         Red            Off         Modem not connected at 2400bps

    12         Red       Blinking fast     Modem connected at 1200bps in
                                                  reliable mode

    12         Red       Blinking slow    Modem connected at 1200bps with
                                                 data compression

    12         Red            Off         Modem not connected at 1200bps

    OH         Red            On                Modem is off-hook

    OH         Red            Off                Modem is on-hook

    TR         Red            On                DTR signal is high

    TR         Red            Off               DTR signal is low

                         Proprietary AT Command Set

                               BLIND DIALING

  Type:          Configuration

  Format:        AT [cmds] Bn [cmds]

  Example:       AT B0 <CR>

  Description:   Selects blind dial or wait-for-dial-tone.

    Command                              Function

   B0           Modem will blind dial.

  B1             Modem will wait for dial tone before dialing.

                                 CD SIGNAL

  Type:          Configuration

  Format:        AT [cmds] &Cn [cmds]

  Example:       AT &C3 $D0<CR>

  Description:   Configures the behavior of the carrier detect signal.

  Command                                Function

  &C0            CD forced high.

   &C1          CD normal.

  &C2            CD forced high except during disconnect.

                                COMMAND SET

  Type:          Configuration

  Format:        AT [cmds] &Qn [cmds]

  Example:       AT &Q0<CR>

  Description:   Selects standard Hayes or custom command sets.

  Command                                Function

   &Q0          Multi-Tech custom command set enabled.

  &Q1            Standard Hayes command set enabled.

                         DIAL STORED PHONE NUMBER

  Type:                 Immediate

  Format:               AT [cmds] Nn1 [Nn2, Nn3...]

  Example:              ATM0 N1N3N5<CR>

  Description:          Dials stored phone number(s). If the first number
                        is busy, the modem will proceed to the next
                        number in the list.

                            DSR/CTS/CD TIMEOUT

  Type:          Register

  Format:        AT [cmds] S24=n [cmds]

  Example:       ATS24=40<CR>

  Default:       20

  Range:         0-255

  Unit:          50 ms

  Description:   Sets the time to drop the DSR, CTS, and CD signals to
                 hangup.

                                DTR DIALING

  Type:          Configuration

  Format:        AT [cmds] $Dn [cmds]

  Example:       AT $D1 DT555-1212<CR>

  Description:   Selects the DTR dialing function.

  Command                                Function

   $D0          DTR dialing disabled.

  $D1            DTR dialing enabled.

                                DTR TIMEOUT

  Type:          Register

  Format:        AT [cmds] S25=n [cmds]

  Example:       ATS25=30<CR>

  Default:       0

  Range:         0-255

  Unit:          .1 second

  Description:   Sets the time to drop the DTR signal to hangup.

  Note:          Setting S25 to 0 sets the DTR timeout to 50 ms.

                                  DUPLEX

  Type:          Configuration

  Format:        AT [cmds] Fn [cmds]

  Example:       AT F1 &W<CR>

  Description:   Controls duplex mode.

  Command                                Function

  F0             Half duplex enabled.

   F1           Full duplex enabled.

                               HELP SCREENS

  Type:          Immediate

  Format:        AT $Hn

  Example:       AT $H1<CR>

  Description:   Shows modem help screens.

    Command                              Function

      $H1        Shows help screen 1.

      $H2        Shows help screen 2.

      $H3        Shows help screen 3.

      $H4        Shows help screen 4.

                            LIST CONFIGURATION

  Type:          Immediate

  Format:        AT Ln

  Example:       AT L5<CR>

  Description:   Lists modem configuration.

    Command                              Function

       L0        Lists all phone numbers in memory.

       L5        Lists all settings.

       L6        Lists the values of all S-registers.

                            LOOPBACK TEST MODE

  Type:          Configuration

  Format:        AT [cmds] Un [cmds]

  Example:       AT U2 &W<CR>

  Description:   Places modem in test mode.

  Command                                Function

       U0        Begin local analog loopback test in originate mode.

       U1        Begin local analog loopback test in answer mode.

       U2        Request remote digital loopback

       U3        Begin local digital loopback.

                                 PROTOCOL

  Type:          Configuration

  Format:        AT [cmds] &Vn [cmds]

  Example:       AT &V1 <CR>

  Description:   Selects the protocol for low-speed data calls.

    Command                              Function

  &V0            Bell protocols.

   &V1          ITU-T protocols.

                                  REDIAL

  Type:          Immediate

  Format:        A:

  Example:       A:

  Description:   Redials the last number dialed until it is no longer
                 busy.

  Note:          Do not precede this command with AT or follow it with
                 <CR>.

                        STORE PHONE NUMBER IN NVRAM

  Type:             Configuration

  Format:           AT [cmds] D<#>N<0-9>

  Example:          ATD1(303)-443-3323N6 <CR>

  Description:      Stores a phone number in the modems memory. Only the
                    dialstring before the N will be stored.

                            WAIT FOR DIAL TONE

  Type:          Immediate

  Format:        AT [cmds] W [cmds]

  Example:       AT W <CR>

  Description:   Wait for new dial tone.

