                  HAYES COMMANDS, S REGISTERS, RS232C PIN-OUTS
        
        
        
         1. AT Commands for the Hayes 1200B and Other Compatible Modems
        
                       Not all commands may work on older Hayes
                        models or on "Hayes-compatible" modems  
        
        
        AT    Attention prefix.  Precedes all command strings except +++ and
              A/
        A/    Repeat previous command line
        +++   Hayes escape code; switches from on-line state to command state.
              Allow 1 second pause before/after escape code entry.  Do not 
              follow with <CR>.
        
        
                                   DIALING COMMANDS
        
        D     Dial
        P     Pulse
        T     Tone
        ,     Pause
        !     Flash
        /     Wait for 1/8 sec.
        @     Wait for silence
        ;     Return to command state after dialing
        
        
        
                                    OTHER COMMANDS
        
         (If a command accepts a numeric prefix, then the command with the
         sub-parameter 0 (zero) is the same as the command with NO numeric
         subparameter.
          For example, ATH0 is the same as ATH, ATM0 is the same as ATM, etc.)
        
        A     Answer call without waiting for ring
        B     CCITT V.22 mode
        B1    Bell 103 & 212A mode
        C     Transmit carrier off
        C1    Carrier on
        E     Characters NOT echoed
        E1    Characters echoed
        F     Half-duplex
        F1    Full-duplex
        H     On hook (hang up)
        H1    Off hook (line and auxiliary relay)
        H2    Off hook (line relay only)
        I     Request product ID code (may be Hayes-specific)
        I1    Test ROM checksum
        I2    Test internal memory
        L0    Low speaker volume
        L1    Low speaker volume






        L2    Medium speaker volume
        L3    High speaker volume
        M     Speaker always off
        M1    Speaker on until carrier detect
        M2    Speaker always on
        O     Go to on-line state
        O1    Remote digital loopback off
        O2    Remote digital loopback request
        Q     Result codes displayed
        Q1    Result codes NOT displayed
        Sr?   Requests current value of modem register 'r'
        Sr=n  Sets modem register 'r' to value 'n'
        V     Show digit result codes
        V1    Show word result codes
        X     Sets baudrate to 300
        X1    Result code CONNECT 1200 enabled
        X2    Enables dial tone detection
        X3    Enables busy signal detection
        X4    Enables dial tone & busy signal detection
        Y     Long space disconnect disabled
        Y1    Long space disconnect disabled
        Z     Software reset; restore default settings
        
        
                                   2. RESULT  CODES
        
        Digit    Word         Description
        -----    ----         --------------------------------------------------
          0      OK ..........Command executed
          1      CONNECT .....Connected at 300 or 1200 bps.  Connected at 300
                              if result of X1, X2, X3 or X4
          2      RING ........Ringing signal detected
          3      NO CARRIER ..Carrier not detected or lost
          4      ERROR .......Illegal cmd, error in cmd line, cmd line exceeds
                              40 chars, invalid char format at 1200 bps, invalid
                              checksum
          5      CONNECT 1200 Connected at 1200 bps.  Results from X1, X2, X3
                              or X4 commands only
          6      NO DIALTONE .Dial tone not detected; subsequent cmds not
                              processed.  Results from X2 or X4 cmds only.
          7      BUSY ........Busy signal detected and subsequent cmds not pro-
                              cessed.  Results from X3 or X4 cmds only.
          8      NO ANSWER ...Silence not detected and subsequent cmds not pro-
                              cessed.  Results from @ cmd only.
        
        
        
                                   3. S  REGISTERS
            Note: almost all have reasonable default values set by ATZ command
        
        Here is a list of the S-registers used by Hayes modem. Please be aware
        that not all modems support these registers and that some modems may
        have more registers than are listed.
        
        ALL S REGISTER COMMANDS ARE ENTERED IN THE AT COMMAND LINE.






        EXAMPLE: AT S8=2 S2=43 S7=30
        TO READ THE VALUE IN ANY REGISTER USE
                 AT SX? <CR>
        THE MODEM SHOULD ECHO THE VALUE FOUND IN THE REGISTER X
        
        
        REG  Values      Register function
        S0   0           AUTO ANSWER OFF
             1-255       AUTO ANSWER ON, ANSWER ON INDICATED # OF RINGS
        S1 **0-255       RING COUNT (THIS IS A READ-ONLY REGISTER)
        S2   0-127       ESCAPE CHARACTER  NORMALLY SET TO 43 OR "+"
             127-255     ESCAPE FUNCTION DISABLED
        S3  0-127        END OF LINE CHARACTER  NORMALLY SET TO 13 (CR)
        S4  0-127        LINE FEED CHARACTER  NORMALLY SET TO 10 (LF)
        S5  0-127        BACKSPACE CHARACTER  NORMALLY SET TO 8 (BS)
        S6  2-255  SEC   PAUSE BEFORE DIALING (NORMALLY 2 SEC)
        S7  1-255  SEC   WAIT FOR CARRIER (NORMALLY SET TO 30 SEC)
        S8  0-255  SEC   PAUSE FOR COMMA IN DIAL STRING (NORMALLY SET TO 2 SEC)
        S9  1-255  .1SEC CARRIER VALIDATION TIME NORMALLY 6 (.6 SEC)
        S10 1-255  .1SEC LOSS OF CARRIER DISCONNECT DELAY NORMALLY 14 (1.4 SEC)
        S11 50-90  .1SEC BETWEEN NUMBER DIAL DELAY.  UNDOCUMENTED.  IMPROVE DIAL
                         SPEED. I LIKE 55. THE DEFAULT IS 90.
        S12 20-255 .02SE ESCAPE SEQUENCE PAUSE  NORMALLY 50 (1.0 SEC)
        S13 *            POWER UP ASYNC DATA FORMAT (USE CHART BELOW)
        S14 *            OPTION STATUS (USE CHART BELOW)
        S16 *            TEST STATUS (USE CHART BELOW)
        S18 0-255 SEC    TEST TIMER (REMOTE TEST)
        S21 *            OPTION STATUS  (USE CHART BELOW)
        S22 *            OPTION STATUS  (USE CHART BELOW)
        S23 *            OPTION STATUS  NORMALLY 07 (USE CHART BELOW)
        S25 0-255 SEC    DTR DETECT DELAY NORMALLY 5 SEC
                         ASYNC MODE, SYIC AUTO-DIAL AND SYIC MANUAL DIAL MODE .05 SEC
        S26 0-255 MS     RTS TO CTS DELAY (1 MS)
        S27 *            OPTION STATUS (USE CHART BELOW)
        
        * REGISTERS USED BY MODEM PROCESSOR. DO NOT ALTER THESE
        ** READ ONLY REGISTERS
        
                      S 13 DATA FORMAT:
        
        POSITION  VALUE  FUNCTION
         BIT 0      -    NOT USED
         BIT 1      -    NOT USED
         BIT 2      0    PARITY OFF
                    1    PARITY ON
         BIT 3      0    ODD PARITY
                    1    EVEN PARITY
         BIT 4      0    7 DATA BITS
                    1    8 DATA BITS
         BIT 5      0    BIT 8=0
                    1    BIT 8=1
         BIT 6      -    NOT USED
         BIT 7      -    NOT USED
        
                     S 14 DATA FORMAT:






         BIT 0      -    NOT USED
         BIT 1      0    LOCAL CHARACTER ECHO OFF
                    1    LOCAL CHARACTER ECHO ON
         BIT 2      0    STATUS DISPLAYS ON
                    1    STATUS DISPLAYS OFF
         BIT 3      0    STATUS CODES SENT
                    1    STATUS MESSAGES SENT
         BIT 4      0    MODEM RESPONDS TO COMMANDS
                    1    MODEM IGNORES COMMANDS
         BIT 5      0    TONE-DIALING
                    1    PULSE-DIALING
         BIT 6      -    NOT USED
         BIT 7      0    ANSWER MODE
                    1    ORIGINATE MODE
        
                      S 16 DATA FORMAT:
         BIT 0      0    ANALOG LOOP OFF
                    1    ANALOG LOOP ACTIVE
         BIT 1      -    NOT USED
         BIT 2      0    DIGITAL LOOP OFF
                    1    DIGITAL LOOP ACTIVE
         BIT 3      0    REMOTE DIGITAL LOOP REQUESTED BY OTHER MODEM IS OFF
                    1    REMOTE DIGITAL LOOP REQUESTED BY OTHER MODEM IS ACTIVE
         BIT 4      0    REMOTE DIGITAL LOOP OFF
                    1    REMOTE DIGITAL LOOP ACTIVE
         BIT 5      0    SELF TEST RDL OFF
                    1    SELF TEST RDL ACTIVE
         BIT 6      0    SELF TEST ANALOG LOOP OFF
                    1    SELF TEST ANALOG LOOP ACTIVE
         BIT 7      -    NOT USED
        
                      S 21 DATA FORMAT:
         BIT 0      0    RJ11/RJ41/45 JACK TYPE
                    1    RJ12/FJ13 JACK TYPE
         BIT 1      -    NOT USED
         BIT 2      0    CTS FOLLOWS RTS
                    1    CTS FORCED ON
         BIT 3&4    0    MODEM IGNORES DTR
                    1    MODEM ASSUMES COMMAND STATE WHEN DTR TURNS OFF
                    2    MODEM ASSUMES COMMAND STATE AND DISABLES AUTO-ANSWER
                         WHEN DTR TURNS OFF
                    3    MODEM RESETS WHEN DTR TURNS OFF
         BIT 5      0    DCD FORCED ON
                    1    DCD FOLLOWS CARRIER
         BIT 6      0    DSR FORCED ON
                    1    DSR BEHAVES NORMALLY
         BIT 7      0    LONG SPACE DISCONNECT DISABLED
                    1    LONG SPACE DISCONNECT ENABLED
        
                      S 22 DATA FORMAT:
         BIT 0&1    1    LOW SPEAKER VOLUME
                    2    MEDIUM SPEAKER VOLUME
                    3    HIGH SPEAKER VOLUME
         BIT 2&3    0    SPEAKER ALWAYS OFF
                    1    SPEAKER ON UNTIL CARRIER DETECTED






                    2    SPEAKER ALWAYS ON
                    3    SPEAKER OFF DURING DIALING THEN ON UNTIL CARRIER DETECTED
         BIT 4&5&6  0    X COMMAND IN EFFECT
                    4    X 1 COMMAND IN EFFECT
                    5    X 2 COMMAND IN EFFECT
                    6    X 3 COMMAND IN EFFECT
                    7    X 4 COMMAND IN EFFECT
         BIT 7      0    39/61 MAKE/BREAK RATIO (PULSE DIALING)
                    1    33/67 MAKE/BREAK RATIO
        
                      S 23 DATA FORMAT:
         BIT 0      0    REMOTE DIGITAL LOOP REQUEST DENIED
                    1    REMOTE DIGITAL LOOP REQUEST GRANTED
         BIT 1&2    0    0-300 BPS
                    1    600 BPS
                    2    1200 BPS
                    3    2400 BPS
         BIT 3      -    NOT USED
         BIT 4&5    0    EVEN PARITY
                    1    PARITY BIT ALWAYS 0
                    2    ODD PARITY
                    3    PARITY BIT ALWAYS 1
         BIT 6&7    0    NO GUARD TONES
                    1    550 HZ GUARD TONE
                    2    1800 HZ GUARD TONE
        
                      S 27 DATA FORMAT:
         BIT 0&1    0    ASYNCHRONOUS MODE
                    1    ASYNC/SYNC MODE
                    2    SYNC AUTO-DIAL
                    3    SYNC MANUAL DIAL
         BIT 2      0    PUBLIC PHONE LINE
                    1    LEASED LINE
         BIT 3      -    NOT USED
         BIT 4&5    0    INTERNAL CLOCK USED
                    1    EXTERNAL CLOCK USED
                    2    SLAVED CLOCK USED
         BIT 6      0    CCITT V.22 PROTOCOL (1200 BPS)
                    1    BELL 212A (1200 BPS)
         BIT 7      -    NOT USED
        
        
                 Specialty Commands
        
        ATB0     CCITT V.22 AT 1200 BPS
        ATB1     BELL 212A AT 1200 BPS *
        AT &F    RESTORE TO FACTORY CONFIGURATION
        AT &G    NO GUARD TONE *
        AT &G1   550 HZ GUARD TONE
        AT &G2   1800 HZ GUARD TONE
        AT &J    RJ11/RJ41S/RJ45 JACK *
        AT &J2   RJ12/RJ13 JACK
        AT &L    REGULAR PHONE LINE *
        AT &L1   LEASED LINE
        AT &M    ASYNC OPERATION *






        AT &M1   ASYNC/SYNC OPERATION
        AT &M2   SYNC AUTO DIAL
        AT &M3   SYNC MANUAL DIAL
        AT &P    39/61 PULSE MAKE/BREAK RATIO *
        AT &P1   33/67 PULSE MAKE/BREAK RATIO
        AT &T4   GRANT RDL TEST REQUEST *
        AT &T5   DENY RDL TEST REQUEST
        AT &W    WRITE CURRENT REGISTERS TO NON-VOL-MEMORY (KEEP FOR POWER UP)
        AT &X    SYNC CLOCK INTERNAL *
        AT &X1   SYNC CLOCK EXTERNAL
        AT &X2   SYNC CLOCK SLAVED
        AT &Z    STORE DIAL COMMAND LINE
        
        DATA INTERFACE (2400)
        AT &C    DCD ALWAYS ON *
        AT &C1   DCD ON WHILE CARRIER PRESENT
        AT &D    DTR IGNORED *
        AT &D1   DTR FAIL DISCONNECT ENABLED (MODEM RETURNS TO COMMAND MODE)
        AT &D2   DTR FAIL DISCONNECT ENABLED (MODEM RETURNS TO COMMAND MODE, TURN
                 AUTO ANSWER OFF)
        AT &D3   DTR FAIL DISCONNECT ENABLED (RESET MODEM)
        
        
        
                             4. RS 232 GENERAL PIN NOTES:
                                   (Compatibility)
        
        Most standard RS232 connector problems are with only several pins:
        (these are not the CBM pin numbers, but the DB25 Pins)
          Pins 2-3 swapped (TD/RD)  (Also a null Modem Configuration)
          Pins 4-5-8 swapped, or tied together (RTS/CTS/DCD)
          Pins 6-20 swapped (DSR/DTR)
          Pins 1-7 tied together (Prot. Gnd/Sig Gnd)
          It should also be noted that most TELECOM failures result from cable
          problems, either intermittent, short or open.  Some manufacturers
          do not solder the wires to the pins, but use crimp connectors.
        
        Pin 1; Protective Ground, to equipment frame.  Further grounding
               may be required, depending upon regulation. (NEEDED)
        
        Pin 2; Transmitted Data.  Generated by data terminal equipment going
               TO transmitting signal converter. (NEEDED)
        
        Pin 3; Received Data. Generated by the receiving signal converter 
               going TO the data terminal equipment. (NEEDED)
        
        Pin 4; Request to Send. Line conditioner.  On half-duplex controls
               the direction of data flow. (NEEDED)
        
        Pin 5; Clear to Send. Generated by the data communication equipment
               to flag if the data is or is not ready to be sent out. (NEEDED)
        
        Pin 6; Data Set Ready. Status of the Local Data Set (to terminal).
        
        Pin 8; Data Carrier Detect. Indicates if the receiving signal






               meets certain parameters. (to terminal)
        
        Pin 9; Plus Test Voltage
        
        Pin 10; Negative Test Voltage
        
        Pin 12; Secondary Line (DCD2)
        
        Pin 13; Secondary Line (CTS2)
        
        Pin 14; Secondary Line (TD2)
        
        Pin 15 & 17; T & R Timing
        
        Pin 16; Secondary Line (RD2)
        
        Pin 19; Secondary Line (RTS2)
        
        Pin 20; Data Terminal Ready (DTR) Controls switching the DCE to the
                communications channel.
        
        Pin 21; Signal Quality Detector. Indicates quality of signal (CCITT
                equiv. 110) (SQ) 
        
        Pin 22; Ring Indicator (CCITT 125, circuit CE)((RI)
        
        Pin 23; Data Signal Rate Selector (for dual baud rate modems)
        
        Pin 24; Transmitter Signal Element Timing (for DTE) 
        
        Pins 11, 18, and 25 are reserved or not used.  Pin 7 is the needed
        Signal Ground, while pin 25 is sometimes used as a busy signal.
        Synchronous Data Transmissions usually use pins 15, 17 and 24 
        (clocks).
        
        A short note about standards:
        RS means Recommended Standard, by the EIA Specs.  Two others 
        'standards' were designated by CCITT using the prefix V and X.  Other
        RS standards are: 269B (synchronous rates); 334 (Signal Quality); 357
        (FAX); 449 (37 Pin connectors) etc. 
         
        This information was compiled from several sources, and should not be
        considered 'Official'. Always consult your modem/interface/computer
        manual for proper usage.




