
3COM CORPORATION

US ROBOTICS WINMODEM 28.8

Card Type                    Fax, Modem (asynchronous)
Chip Set                     U.S. Robotics
Maximum Data Rate            28.8Kbps
Maximum Fax Rate             14.4Kbps
Data Bus                     8-bit ISA
Fax Class                    Class I & II
Data Modulation Protocol     Bell 103/212A

                             ITU-T V.21, V.22, V.22bis, V.23, V.25, V.32,
                             V.32bis, V.34
Fax Modulation Protocol      ITU-T V.17, V.21CH2, V.27ter, V.29
Error Correction/Compression MNP5, V.42, V.42bis

[Image]

                                CONNECTIONS

         Function            Label            Function             Label

  Line in                         CN1       Line out                CN2

                         Proprietary AT Command Set

                                  ANSWER

  Type:                Immediate

  Format:              AT [cmds] A

  Description:         Enables manual answer mode, the modem goes
                       off-hook; pressing any key will abort.

                                   ABORT

  Type:          Immediate

  Format:        Any key

  Description:   Aborts answering/originating a call; modem hangs up.

                              ANSWER SEQUENCE

  Type:          Configuration

  Format:        AT [cmds] Bn [cmds]

  Description:   Selects the answer sequence the modem will use

    Command                              Function

       B0        ITU-T answer sequence enabled

       B1        U.S.(Bell) answer sequence enabled

                                 ATTENTION

  Type:              Immediate

  Format:            AT [cmds]

  Description:       Tells the modem that a command follows or use alone
                     to test OK result code

                          BIT-MAPPED REGISTER S13

  Format                AT [cmds] S13=n [cmds]

  Default:              0

  Range:                0-159

  Unit:                 Bit-mapped

  Description:          Controls DTR reset, non-error-correcting mode
                        buffer, DTR dialing, reset dialing, and
                        disconnect.

   Bit       Value                          Function

    0               0   DTR normal

                   1    Reset on low DTR

    1               0   Non-error-correcting mode transmit buffer set to
                        1.5KB
                   1
                        Non-error-correcting mode transmit buffer set to
                        128 bytes

    2               0   Use backspace key for delete disabled

                   1    Use backspace key for delete enabled

    3               0   DTR dialing disabled

                   1    DTR dialing enabled

    4               0   Reset dialing disabled

                   1    Reset dialing enabled, dials number at position 0
                        in NVRAM.

   6, 5           00    Not used

    7               0   Disconnect as normal

                   1    Disconnect on escape code

                          BIT-MAPPED REGISTER S15

  Format              AT [cmds] S15=n [cmds]

  Default:            0

  Range:              0-255

  Unit:               Bit-mapped

  Description:        Controls ARQ/MNP for V.22/22bis/32/32bis/32terbo,
                      V.42 detection, MNP4 and 3, and MNP
                      incompatibility.

   Bit      Value                          Function

    0             0   Error correction and data compression enabled for
                      V.22
                 1
                      Error correction and data compression disabled for
                      V.22

    1             0   Error correction and data compression enabled for
                      V.22bis
                 1
                      Error correction and data compression disabled for
                      V.22bis

    2             0   Error correction and data compression enabled for
                      V.32/32bis/32terbo
                 1
                      Error correction and data compression disabled for
                      V.32/32bis/32terbo

  7, 3          00    V.42 detection disabled

    4             0   MNP 4 enabled

                 1    MNP 4 disabled

    5             0   MNP 3 enabled

                 1    MNP 3 disabled

    6             0   MNP normal

                 1    MNP adjusted for non compliant modems

                          BIT-MAPPED REGISTER S27

  Format                 AT [cmds] S27=n [cmds]

  Default:               0

  Range:                 0-191

  Unit:                  Bit-mapped

  Description:           Controls V.21, V.32 encoding and modulation,
                         V.42 answer tone and handshake, and 9600 result
                         codes.

    Bit       Value                          Function

     0                0  V.21 disabled

                     1   V.21 enabled

     1                0  V.32 non-trellis coding disabled

                     1   V.32 non-trellis coding enabled

     2                0  V.32 modulation enabled

                     1   V.32 modulation disabled

     3                0  2100Hz answer tone enabled

                     1   2100Hz answer tone disabled

     4                0  V.23 fallback mode disabled

                     1   V.23 fallback mode enabled

     5                0  V.32bis enabled

                     1   V.32bis disabled

     6               0   Not used

     7                0  Actual result codes displayed

                     1   Force 9600 result codes

                          BIT-MAPPED REGISTER S32

  Format:            AT [cmds] S32=n [cmds]

  Default:           2

  Range:             0-27

  Description:       Controls call indicate, V.8, V.34, and 33.6Kbps
                     support

  Note: For 28.8 models

     Bit      Value                         Function

      0             0  Call indicate during V.34 operation disabled

                   1   Call indicate during V.34 operation enabled

      1             0   V.8 during V.34 operation disabled

                   1    V.8 during V.34 operation enabled

      2            0    Not used

      3             0   V.34 enabled

                   1    V.34 disabled

      4             0   33.6Kbps support enabled

                   1    33.6Kbps support disabled

                          BIT-MAPPED REGISTER S33

  Format:          AT [cmds] S33=n [cmds]

  Default:         0

  Range:           0-191

  Description:     Controls baud rate and shaping.

  Note: For 28.8 models

   Bit    Value                           Function

    0          0   2400 baud rate enabled

              1    2400 baud rate disabled

    1          0   2743 baud rate enabled

              1    2743 baud rate disabled

    2          0   2800 baud rate enabled

              1    2800 baud rate disabled

    3          0   3000 baud rate enabled

              1    3000 baud rate disabled

    4          0   3200 baud rate enabled

              1    3200 baud rate disabled

    5          0   3429 baud rate enabled

              1    3429 baud rate disabled

    6         0    Not used

    7          0   Shaping enabled

              1    Shaping disabled

                          BIT-MAPPED REGISTER S34

  Format:               AT [cmds] S34=n [cmds]

  Default:              0

  Range:                0-255

  Description:          Controls mapping, non-linear coding, TX level
                        deviation, pre-emphasis, and pre-coding.

  Note: For 28.8 models

    Bit      Value                          Function

     0              0   8S-2D map enabled

                   1    8S-2D map disabled

     1              0   16S-4D map enabled

                   1    16S-4D map disabled

     2              0   32S-2D map enabled

                   1    32S-2D map disabled

     3              0   64S-4D map enabled

                   1    64S-4D map disabled

     4              0   Non linear coding enabled

                   1    Non linear coding disabled

     5              0   TX level deviation enabled

                   1    TX level deviation disabled

     6              0   Pre-emphasis enabled

                   1    Pre-emphasis disabled

     7              0   Pre-coding enabled

                   1    Pre-coding disabled

                               BREAK LENGTH

  Type:            Register

  Format:          AT [cmds] S21=n [cmds]

  Default:         10

  Range:           Unidentified

  Unit:            .01 second

  Description:     Sets the length of error control mode breaks sent from
                   DCE to DTE.

                                BREAK TYPE

  Type:          Configuration

  Format:        AT [cmds] &Yn [cmds]

  Description:   Configures action of break signal

    Command                              Function

      &Y0        Empty buffer only

      &Y1        Empties buffer and break is sent immediately

      &Y2        Do not empty buffer and break is sent immediately

                            CARRIER DETECT (CD)

  Type:          Configuration

  Format:        AT [cmds] &Cn [cmds]

  Description:   Controls the CD signal

    Command                              Function

      &C0        Modem does not respond to CD signal

      &C1        CD signal normal

                                COMPRESSION

  Type:          Configuration

  Format:        AT [cmds] &Kn [cmds]

  Description:   Selects data compression

    Command                              Function

      &K0        Data compression disabled

      &K1        Auto enabled/disable data compression

      &K2        Data compression enabled

      &K3        MNP5 data compression disabled

                       CONNECTION SPEED LOWER LIMIT

  Type:          Configuration

  Format:        AT [cmds] &Un [cmds]

  Description:   Sets minimum required connection speed

            Note: 16.8 - 28.8bps for 28.8 models

    Command                              Function

      &U0        Disabled

      &U1        300bps

      &U2        1200bps

      &U3        2400bps

      &U4        4800bps

      &U5        7200bps

      &U6        9600bps

      &U7        12Kbps

      &U8        14.4Kbps

      &U9        16.8Kbps

      &U10       19.2Kbps

      &U11       21.6Kbps

      &U12       24Kbps

      &U13       26.4Kbps

      &U14       28.8Kbps

                       CONNECTION SPEED UPPER LIMIT

  Type:                Configuration

  Format:              AT [cmds] &Nn [cmds]

  Description:         Sets maximum required connection speed, modem will
                       hang up if it cannot connect.

            Note: 16.8 - 28.8bps for 28.8 models

       Command                              Function

         &N0           Variable

         &N1           300bps

         &N2           1200bps

         &N3           2400bps

         &N4           4800bps

         &N5           7200bps

         &N6           9600bps

         &N7           12Kbps

         &N8           14.4Kbps

         &N9           16.8Kbps

        &N10           19.2Kbps

        &N11           21.6Kbps

        &N12           24Kbps

        &N13           26.4Kbps

        &N14           28.8Kbps

                           DATA SET READY (DSR)

  Type:          Configuration

  Format:        AT [cmds] &Sn [cmds]

  Description:   Selects DSR options

    Command                              Function

      &S0        DSR forced high

      &S1        DSR controlled by modem

                         DATA TERMINAL READY (DTR)

  Type:          Configuration

  Format:        AT [cmds] &Dn [cmds]

  Description:   Selects modem response to DTR

    Command                              Function

      &D0        Modem does not respond to DTR

      &D1        Modem goes to command mode after DTR toggles

      &D2        Modem uses DTR as normal

                                   DIAL

  Type:                 Immediate

  Format:               AT [cmds] D<#> [cmds]

  Example:              ATDT 443-3388,,,1111;

  Description:          Dials telephone number according to any modifiers
                        included in the string

  Note:                 Any combination of modifiers can be used to
                        produce the desired dial functions in sequence.

        Command                             Function

           P            Pulse dialing enabled

           T            Tone dialing enabled

           ,            Dialing paused for 2 seconds to a maximum amount
                        of time specified in S8 register

           ;            Modem returned to command state after dialing.
                        Can only be placed at the end of the dial
                        command.

           "            Dials letters that follow, ATDT"GOMICRO

           !            Flash function initiated

           /            125 ms delay before proceeding with dial string

           W            Dialing resumed following dial tone detection of
                        second dial tone

           @            Wait for quiet answer, then procedes to execute
                        the rest of the dial string.

           R            Answer mode enabled; originate mode disabled
                        following handshake initiation.

        # and *         Extended touch tone pad tones

                            DIAL - LAST NUMBER

  Type:          Immediate

  Format:        AT [cmds] DL [cmds]

  Description:   Re-dial last number dialed

                           DIAL - STORED NUMBER

  Type:          Immediate

  Format:        AT [cmds] DSn [cmds]

  Description:   Dial stored number from memory location n

                          DISCONNECT BUFFER DELAY

  Type:                  Register

  Format                 AT [cmds] S38=n [cmds]

  Default:               0

  Range:                 Unidentified

  Unit:                  1 second

  Description:           Sets maximum duration allowed during buffered
                         data calls for modem to perform clearing
                         functions after losing carrier-signal or
                         receiving a clear call signal from the remote
                         modem and before initiating hang-up process. A
                         value of 0 will allow the modem to hanging-up
                         after DTR drops.

                           DTR CHANGE THRESHOLD

  Type:           Register

  Format          AT [cmds] S25=n [cmds]

  Default:        20

  Range:          Unidentified

  Unit:           .01 second

  Description:    Sets maximum time a change in the DTR signal will be
                  ignored

                                   ECHO

  Type:            Configuration

  Format:          AT [cmds] En [cmds]

  Description:     Controls echo function; display keyboard commands when
                   enabled.

     Command                             Function

       E0          Echo function disabled

       E1          Echo function enabled

                              ECHO - ON-LINE

  Type:          Configuration

  Format:        AT [cmds] Fn [cmds]

  Description:   Selects whether data sent while in data mode are echoed

    Command                              Function

       F0        Local echo enabled

       F1        Local echo disabled

                        ERROR CORRECTION MODE (ARQ)

  Type:          Configuration

  Format:        AT [cmds] &Mn [cmds]

  Description:   Selects active error correction protocols

    Command                              Function

      &M0        Normal mode only

      &M4        Auto-detect mode

      &M5        ARQ mode only

                              ESCAPE SEQUENCE

  Type:                   Immediate

  Format:                 +++AT [cmds] <CR>

  Description:            Initiates the escape sequence and returns the
                          modem to the on-line command state if it
                          receives three escape characters set in S2
                          within the time allotted by S12.

            Note: Do not precede this command with AT.

                           EXTENDED RESULT CODES

  Type:          Configuration

  Format:        AT [cmds] &An [cmds]

  Description:   Selects extended result codes

    Command                              Function

      &A0        Extended result codes disabled

      &A1        ARQ result codes enabled

      &A2        ARQ result codes enabled and V.32 result code added

      &A3        Error control and compression result codes enabled

                          FACTORY DEFAULT PROFILE

  Type:                  Configuration

  Format:                AT [cmds] &Fn [cmds]

  Description:           Loads values in active profile to values found
                         in the default profile, which are READ-ONLY.

        Command                              Function

          &F0             Generic template

          &F1             Hardware flow control template

          &F2             Software flow control template

                       FLOW CONTROL CHARACTER - XOFF

  Type:          Register

  Format:        AT [cmds] S23=n [cmds]

  Default:       19

  Range:         0-127

  Unit:          ASCII

  Description:   Sets the character used to represent XOFF.

                       FLOW CONTROL CHARACTER - XON

  Type:          Register

  Format:        AT [cmds] S22=n [cmds]

  Default:       17

  Range:         0-127

  Unit:          ASCII

  Description:   Sets the character used to represent XON.

                         FLOW CONTROL PASSTHROUGH

  Type:          Configuration

  Format:        AT [cmds] &In [cmds]

  Description:   Allows modem to act on, then transmit XON/XOFF
                 characters.

    Command                              Function

      &I0        Software flow control disabled

      &I1        XON/XOFF pass-through enabled

      &I2        XON/XOFF pass-through disabled

                     FLOW CONTROL TYPE - RECEIVE DATA

  Type:           Configuration

  Format:         AT [cmds] &Rn [cmds]

  Description:    Controls receive data hardware flow control and RTS
                  signals

    Command                              Function

      &R1         Modem ignores RTS

      &R2         Received data to DTE when RTS is on

                     FLOW CONTROL TYPE - TRANSMIT DATA

  Type:          Configuration

  Format:        AT [cmds] &Hn [cmds]

  Description:   Sets type of flow control used by modem

    Command                              Function

      &H0        Flow control disabled

      &H1        CTS/RTS flow control enabled

      &H2        XON/XOFF flow control enabled

      &H3        CTS/RTS and XON/XOFF flow control enabled

                                GUARD TONE

  Type:          Configuration

  Format:        AT [cmds] &Gn [cmds]

  Description:   Commands the modem to transmit a guard tone

            Note: Used primarily for international data transmission

    Command                              Function

      &G0        Guard tone disabled

      &G1        550Hz guard tone enabled

      &G2        1800Hz guard tone enabled

                          HELP SCREEN - CONTROLS

  Type:          Immediate

  Format:        <Ctrl> C, K or S

  Description:   Cancel or starts/restarts help screens

    Command                              Function

    <Ctrl> C      Display of help screen canceled

    <Ctrl> K      Display of help screen canceled

    <Ctrl> S      Starts/restarts help screens

                               HOOK CONTROL

  Type:          Immediate

  Format:        AT [cmds] Hn [cmds]

  Description:   Selects whether the modem is on-hook or off-hook

    Command                              Function

       H0        Modem commanded to go on-hook (hang-up)

       H1        Modem commanded to go off-hook (pick-up)

                             INACTIVITY TIMER

  Type:                  Register

  Format:                AT [cmds] S19=n [cmds]

  Default:               0

  Range:                 Unidentified

  Unit:                  1 minute

  Description:           Sets the length of time that the modem does not
                         receive information before it disconnects.

                          LIST AMPERSAND COMMANDS

  Type:          Immediate

  Format:        AT [cmds] &$ [cmds]

  Description:   Displays ampersand (&) commands

                            LIST DIAL COMMANDS

  Type:          Immediate

  Format:        AT [cmds] D$ [cmds]

  Description:   Displays dial commands

                             LIST S-REGISTERS

  Type:          Immediate

  Format:        AT [cmds] S$ [cmds]

  Description:   Displays the S-registers

                             LOCK SERIAL PORT

  Type:              Configuration

  Format:            AT [cmds] &Bn [cmds]

  Description:       Not used. Modem follows COM port speed if it
                     changes, even while on-line.

                                  ON-LINE

  Type:           Immediate

  Format:         AT [cmds] On [cmds]

  Description:    Controls on-line command (data transmission) mode
                  options.

            Note: The O command must be placed at the end of the command
            string.

     Command                             Function

       O0         On-line command mode with no retraining enabled

       O1         On-line command mode with retraining enabled

                               ON-LINE HELP

  Type:          Immediate

  Format:        AT [cmds] $ [cmds]

  Description:   On-line help; displays basic command list

                    POWER-UP/HARD RESET CONFIGURATIONS

  Type:          Configuration

  Format:        AT [cmds] Yn [cmds]

  Description:   On power-up modem uses default profiles

    Command                              Function

       Y0        Use default setting 0 saved in non-volatile RAM

       Y1        Use default setting 1 saved in non-volatile RAM

       Y2        Generic template

       Y3        Hardware flow control template

       Y4        Software flow control template

                               PULSE DIALING

  Type:              Configuration

  Format:            AT [cmds] P [cmds]

  Description:       Enables pulse dialing

            Note: This command can be duplicated with the P modifier in
            the D (Dial) command.

                            PULSE DIALING RATIO

  Type:          Configuration

  Format:        AT [cmds] &Pn [cmds]

  Description:   Selects pulse dial make/break ratio

    Command                              Function

      &P0        39/61ms at 10pps (North America)

      &P1        33/67ms at 10pps (Europe)

                           REPEAT COMMAND STRING

  Type:             Configuration

  Format:           AT [cmds] A> [cmds]

  Description:      Causes modem to repeat command string until a
                    keyboard key is pressed

                          REPEAT PREVIOUS COMMAND

  Type:           Immediate

  Format:         A/

  Description:    Repeats previous command, mainly used for re-dial

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

                            REPORT INFORMATION

  Type:          Immediate

  Format:        AT [cmds] In [cmds]

  Description:   Displays information requested

    Command                              Function

       I0        Reports 4-digit product code

       I1        Reports DSP code checksum

       I2        Reports RAM test

       I3        Reports product type

       I4        Reports current command settings

       I5        Reports NVRAM settings

       I6        Reports link diagnostics

       I7        Reports product configuration

      I10        VxD configuration

                               RESULT CODES

  Type:          Configuration

  Format:        AT [cmds] Qn [cmds]

  Description:   Enables modem to send result codes to the DTE

    Command                              Function

       Q0        Result code sending enabled

       Q1        Result code sending disabled

       Q2        Result code sending enabled while in originate mode

                            RESULT CODE FORMAT

  Type:             Configuration

  Format:           AT [cmds] Vn [cmds]

  Description:      Selects word or numeric format for information-text
                    and result codes

     Command                              Function

        V0          Numeric format enabled

        V1          Verbose (word) format enabled

                     SELECT CALL PROGRESS RESULT CODES

  Type:                  Configuration

  Format:                AT [cmds] Xn [cmds]

  Description:           Enables selection of tone detection and
                         associated result code format options

        Command                              Function

           X0            Busy and dial tone detection disabled; result
                         codes 0-4 enabled.

           X1            Busy and dial tone detection disabled; result
                         codes 0-5, 10-155 enabled.

           X2            Busy tone detection disabled, dial tone
                         detection enabled; result codes 0-6, 10-155
                         enabled; also adaptive dialing, wait for second
                         dial tone, and fast dialing enabled.

           X3            Busy tone detection enabled, dial tone detection
                         disabled; result codes 0-5, 7-155 enabled; also
                         adaptive dialing, and wait for answer enabled.

           X4            Busy and dial tone detection enabled; result
                         codes 0-155 enabled; also adaptive dialing, wait
                         for second dial tone, wait for answer, and fast
                         dialing enabled.

  Note: Valid numeric result codes; 0-8, 10, 13, 18, 20, 21, 25, 43, 85,
  91, 99, 103, 107, 151, and 155.

                                SOFT RESET

  Type:           Immediate

  Format:         AT [cmds] Zn [cmds]

  Description:    Restores modem profiles previously saved in
                  non-volatile RAM

    Command                              Function

       Z0         Restore setting used by ATY command

       Z1         Restore setting 0

       Z2         Restore setting 1

       Z3         Restore factory setting 0 (AT&F0)

       Z4         Restore factory setting 1 (AT&F1)

       Z5         Restore factory setting 2 (AT&F2)

                               SPEAKER MODE

  Type:                Configuration

  Format:              AT [cmds] Mn [cmds]

  Description:         Selects various speaker options

       Command                             Function

         M0            Speaker disabled

         M1            Speaker enabled until carrier signal detected

         M2            Speaker enabled

         M3            Speaker enabled following dialing, then disabled
                       after carrier signal detected.

                              SPEAKER VOLUME

  Type:          Configuration

  Format:        AT [cmds] Ln [cmds]

  Description:   Controls speaker volume

    Command                              Function

       L0        Low volume setting

       L1        Low volume setting

       L2        Medium volume setting

       L3        Highest volume setting

                              STATUS-REGISTER

  Type:               Configuration

  Format:             Read: AT [cmds] Sn? [cmds]

                      Write: AT [cmds] Sn=x [cmds]

  Description:        Writes to or reads from a specified register

            Note: See the section on S-registers for detailed listing of
            commonly used S-registers.

       Command                             Function

       Sn.b=x         Write to register bit b using values 0 (off) and 1
                      (on) for x

                           STORE ACTIVE PROFILE

  Type:               Configuration

  Format:             AT [cmds] &Wn [cmds]

  Description:        Writes the values for the active profile into the
                      non-volatile RAM templates

      Command                              Function

        &W0           Write the active profile to stored profile 0

        &W1           Write the active profile to stored profile 1

                          STORE TELEPHONE NUMBER

  Type:               Configuration

  Format:             AT [cmds] &Zn=x

  Description:        Writes selected telephone numbers into the
                      non-volatile memory at location n

            Note: The characters described in the D command are valid for
            use in the &Z command.

       Command                             Function

        &Zn=L         Writes last executed dial string into the
                      non-volatile memory at location n

        &Zn?          Displays phone number from non-volatile memory at
                      location n

                                TEST MODES

  Type:              Configuration

  Format:            AT [cmds] &Tn [cmds]

  Description:       Controls loopback tests, analog, digital, remote
                     digital, and self tests.

      Command                              Function

        &T0          Testing disabled

        &T1          Local analog loopback enabled

        &T3          Local digital loopback enabled

        &T4          Remote digital loopback enabled

        &T5          Remote digital loopback prohibited

        &T6          Remote digital loopback initiated

        &T7          Remote digital loopback w/ self-test and error
                     detector in progress

        &T8          Local analog loopback w/ self-test and error
                     detector in progress

                                TEST TIMER

  Type:           Register

  Format          AT [cmds] S18=n [cmds]

  Default:        0

  Range:          0-255

  Unit:           1 second

  Description:    Sets the maximum duration for modem tests

            Note: S18=0 disables the timer and allows an indefinite
            duration.

                               TONE DIALING

  Type:              Configuration

  Format:            AT [cmds] T [cmds]

  Description:       Enables tone dialing mode

            Note: This command can be duplicated with the T modifier in
            the D (Dial) command.

                             TONE DIALING TEST

  Type:          Register

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

  Description:   Selects the tone dialing test

    Command                              Function

     S16=0       Tone dialing test disabled

     S16=2       Tone dialing test enabled

                     V.21 - ANSWER MODE FALLBACK TIMER

  Type:          Register

  Format:        AT [cmds] S29=n [cmds]

  Default:       20

  Range:         Unidentified

  Unit:          .1 second

  Description:   Sets the length of time for V.21 answer mode fallback

                            V.32 HANDSHAKE TIME

  Type:          Register

  Format:        AT [cmds] S28=n [cmds]

  Default:       8

  Range:         0-255

  Unit:          .1 second

  Description:   Sets length of V.32 handshake

     Value                                Meaning

       0          V.32 answer tones disabled

      255         V.32 at 9600 enabled, all other connections disabled.

