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                     Hayes Compatible Modem Command Set

       +++    Standard escape sequence (see register S2)
       Comma  Standard pause character (see register S8)
       AT     Standard attention sequence

       ATA    Force immediate answer
       ATC0   Transmitter off
       ATC1   Transmitter on

       ATD    Dial (ATD number)
       ATDP   Pulse dial (ATDP number)
       ATDT   Tone dial (ATDT number)

       ATE0   Disable local character echo
       ATE1   Enable local character echo
       ATF0   Half Duplex (modem echoes characters)
       ATF1   Full Duplex (modem does not echo characters)

       ATH0   Force line on hook
       ATH1   Force line off hook
       ATH2   Force line special off hook (used for HAM radio)

       ATI0   Request product code, formatted PPR, PP=prod., R=rev.
       ATI1   Request ROM check sum

       ATL1   Speaker volume low  (modem specific)
       ATL2   Speaker volume medium  (modem specific)
       ATL3   Speaker volume high  (modem specific)
       ATM0   Speaker always off
       ATM1   Speaker on except while carrier present
       ATM2   Speaker always on
       ATM3   Speaker on except while dialing and carrier present

       ATO    Force modem into online state
       ATP    Sets modem to default pulse dial

       ATQ0   Results codes are to be sent
       ATQ1   Result codes are not sent

       ATR    Sets modem to answer mode after dialing out
       ATSn   Where Sn is S register number 'n' (see registers below)
       ATT    Sets modem to default tone dial

       ATV0   Send word result codes
       ATV1   Send numeric codes

       ATX0   Basic result code set "CONNECT", no dial tone detect
       ATX1   Extended result code set "CONNECT 1200", no dialtone detect
       ATX2   Wait for dial tone, extended result codes
       ATX3   Detect busy signal, extended result codes
       ATX4   Wait for dial tone, detect busy, extended result codes

       ATZ    Reset to power up condition

                    Hayes 2400 Compatible Modem Commands

       ATB0    CCITT V.22 at 1200 bps
       ATB1    BELL 212A at 1200 bps

       AT&C    DCD always on
       AT&C1   DCD on while carrier present

       AT&D    DTR ignored
       AT&D1   DTR fail disconnect enabled
       AT&D2   DTR fail disconnect enabled (auto answer off)
       AT&D3   DTR fail disconnect enabled (reset modem)

       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-volatile memory
       AT&X    Sync clock internal
       AT&X1   Sync clock external
       AT&X2   Sync clock slaved
       AT&Z    Store dial command line

                      Hayes Compatible Modem Registers

       Not all modems support all of these registers and some modems have
       registers other than those listed here.  Also note, some are read only.

       To set a register use:         AT Sr=##  (cr)
       To read the register:          AT Sr?    (cr)

       Where "r" is the register and (cr) is a carriage return

       The following represent conventions used in the tables below:

       () indicates defaults for Smartmodem 1200
       ** indicates possible inconsistencies across modems

       Reg  Values        Register Function

       S0   0-255    Ring to answer on (0=don't answer)
       S1   0-255    Ring count (clear after 8 sec) (read only)
       S2   0-255    Escape char, normally "+", 128-255 disable escape
       S3   0-127    End of line character (0x0D/CR)
       S4   0-127    Line feed character (0x0A/LF)
       S5   0-32,127 Backspace character (0x08/BS)
       S6   2-255    Pause before dialing in seconds (2)
       S7   1-255    Wait for carrier in seconds (30)
       S8   0-255    Pause for comma in dial string in seconds (2)
       S9   1-255    Carrier detect response time in 1/10 second (6)
       S10  1-255    Carrier loss delay in 1/10 second, 255=ignore CD (7)
       S11 50-255    Touch tone dial speed, in milliseconds (70)
       S12 20-255    Escape guard time, in 1/50 second,0=no delay (50)
S13 power up async data format
Bit Dec Hex  Description
0 1 01h  Not used
1 2 02h  Result code, 0=basic, 1=extended
2 4 04h  Parity, 0=disabled, 1=enabled
3 8 08h  Parity, 0=odd ,1=even
4 16 10h  Data bits, 0=7 bits, 1=8 bits
5 32 20h  Undefined
6 64 40h  Buffer ovfw flag, 0=disabled,1=enabled
7 128 80h  8th bit, 0=space,1=mark (8 bit only)

 

S14 option register status data format
Bit Dec Hex  Description
0 1 01h  Not used **
1 2 02h  Local echo, 0=disabled, 1=enabled
2 4 04h  Result codes, 0=enabled,1=disabled
3 8 08h  Result codes, 0=numeric,1=word
4 16 10h  Command recognition, 0=enable,1=disable
5 32 20h  Dial method, 0=touch tone, 1=pulse
6 64 40h  Not used **
7 128 80h  0=answer, 1=originate ** 
       S15           Flag register **
S16 test status
Bit Dec Hex  Description
0 1 01h  Analog loop, 0=inactive, 1=active
1 2 02h  Not used
2 4 04h  Digital loop, 0=inactive, 1=active
3 8 08h  Remote req digital loop,0=inact.,1=active
4 16 10h  Remote digital loop,0=inact.,1=active
5 32 20h  Self test RDL, 0=inactive, 1=active
6 64 40h  Self test analog loop,0=inactive,1=active
7 128 80h  Unused 
       S18 0-255     Remote test timer in seconds
S21 option status
Bit Dec Hex  Description
0 1 01h  Jack type, 0=RJ11,RJ41,RJ45,1=RJ12,RJ13
1 2 02h  Not used
2 4 04h  CTS state,  0=follows RTS, 1=forced on
3 8 08h  DTR modem behavior (see below)
4 16 10h
5 32 20h  DCD, 0=forced on, 1=follows carrier
6 64 40h  DSR, 0=forced on, 1=behaves normally
7 128 80h  Long space disconnect,0=disabled,1=enabled 
       DTR modem behavior (bits 4 and 3):
        00  Ignore DTR
        01  Assume command state when DTR drops
        10  Assume command state and disable auto-answer when DTR drops
        11  Reset when DTR drops
S22 option status
Bit Dec Hex  Description
0 1 01h  Speaker volume, 01=low,10=med,11=high
1 2 02h
2 4 04h  Speaker setting (see below)
3 8 08h
4 16 10h  X command in effect
5 32 20h
6 64 40h
7 128 80h  Make/break ratio, 0=39/61, 1=33/67 
       S22 Speaker setting (bits 3 and 2):
        00  Speaker always off
        01  Speaker on until carrier detected
        10  Speaker always on
        11  Speaker off during dialing, then on until CD

       S22 X command in effect (bits 6, 5 and 4):
       100  X1 command in effect   101  X2 command in effect
       101  X2 command in effect   110  X3 command in effect
       100  X1 command in effect   111  X4 command in effect
S23 option status
Bit Dec Hex  Description
0 1 01h  Remote dig.loop request,0=denied,1=ok
1 2 02h  Baud rate (see table)
2 4 04h
3 8 08h  Not used
4 16 10h  Parity (see table)
5 32 20h
6 64 40h  Guard tone setting
7 128 80h 
       S23 Baud rate table (bits 2 and 1):
        00   0-300 bps         01     600 bps
        10    1200 bps         11    2400 bps
       S23 Parity setting (bits 5 and 4):
        00   Even parity       01   Parity bit always 0
        10   Odd parity        11   Parity bit always 1
       S23 Guard Tone Setting (bits 7 and 6):
        00    No guard tones
        01    550 hz guard tone
        10    1800 hz guard tone

       S25 0-255     DTR detect delay in seconds (5)
       S26 0-255     RTS to CTS delay in milli-seconds (1)
S27 option status
Bit Dec Hex  Description
0 1 01h  Synch/async mode (see table)
1 2 02h
2 4 04h  Phone line, 0= public, 1=leased
3 8 08h  Not used
4 16 10h  Clock type (see table)
5 32 20h
6 64 40h  Protocol, 0=CCITT V.22, 1=Bell 212A
7 128 80h  Not used 
       S27 Sync/Async mode (bits 1 and 0):
        00   Asynchronous mode       01   Async/sync mode
        10   Sync auto-dial          11   Sync manual dial
       S27 Clock Type (bits 4 and 5):
        00   Internal clock used     01   External clock used
        10   Slaved clock used

        Fax Commands

        +FCLASS?        Mode query
        +FCLASS=n       Fax mode selection
        +FCLASS=?       Supported modes
        +FRH=      Receive HDLC data
        +FRM=      Receive data
        +FRS=Wait for ?????
        +FTH=      Transmit DDLC data
        +FTM=      Transmit data
        +FTS=Stop transmission and pause
        +FMFR?          Identify modem manufacturer
        +FMLD?          Identify product model
        +FREV?          Identify product revision
        +FTTn           Fax transmit test command
        +FRTn           Fax receive test command

        Voice AT Commands

        #VBP            Generate beep tone
        #VCL            Voice mode selection
        #VCSD           Command mode silence detection
        #VCPC=n         Input pin character selection
        #VCPS=n         Input pin function selection
        #VIN            Read general purpose input pins
        #VIN=n          Initialise parameter
        #VLN=a          Relay ??? control
        #VOUT=n         Write to general purpose output pins
        #VPE            Telephone emulation mode
        #VPL            Play level
        #VPY            Play mode
        #VRD            Record mode
        #VRL=n          Record level
        #VSL=n          Record silence threshold level
        #VSM=n          Sampling mode
        #VSQT=n         Record 'q' silence time

        #VSR=n          Sampling rate
        #VSST=n         Record 'n' silence time


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