HelpPC 2.10 Quick Reference Utility Copyright 1991 David Jurgens

                     Hayes Command Set / Register Formats

       +++    standard escape sequence (see S2 below)
       Comma  standard pause character (see S8 below)
       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 on-line state
       ATP    sets modem to default pulse dial

       ATQ0   modem returns result codes
       ATQ1   modem does not return result codes

       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 numeric codes
       ATV1   send word result 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)

       │7│6│5│4│3│2│1│0│  S13   power up async data format
        │ │ │ │ │ │ │ └──── unused
        │ │ │ │ │ │ └───── result code, 0=basic, 1=extended
        │ │ │ │ │ └────── parity, 0=disabled, 1=enabled
        │ │ │ │ └─────── parity, 0=odd ,1=even
        │ │ │ └──────── data bits, 0=7 bits, 1=8 bits
        │ │ └───────── undefined
        │ └────────── buffer ovfw flag, 0=disabled,1=enabled
        └─────────── 8th bit, 0=space,1=mark (8 bit only)

       │7│6│5│4│3│2│1│0│  S14   option register status data format
        │ │ │ │ │ │ │ └──── unused **
        │ │ │ │ │ │ └───── local echo, 0=disabled, 1=enabled
        │ │ │ │ │ └────── result codes, 0=enabled,1=disabled
        │ │ │ │ └─────── result codes, 0=numeric,1=word
        │ │ │ └──────── command recognition, 0=enable,1=disable
        │ │ └───────── dial method, 0=touch tone, 1=pulse
        │ └────────── unused **
        └─────────── 0=answer, 1=originate **

       S15           flag register **

       │7│6│5│4│3│2│1│0│  S16   test status
        │ │ │ │ │ │ │ └──── analog loop, 0=inactive, 1=active
        │ │ │ │ │ │ └───── unused
        │ │ │ │ │ └────── digital loop, 0=inactive, 1=active
        │ │ │ │ └─────── remote req digital loop,0=inact.,1=active
        │ │ │ └──────── remote digital loop,0=inact.,1=active
        │ │ └───────── self test RDL, 0=inactive, 1=active
        │ └────────── self test analog loop,0=inactive,1=active
        └─────────── unused

       S18 0-255     remote test timer in seconds

       │7│6│5│4│3│2│1│0│  S21   option status
        │ │ │ │ │ │ │ └──── jack type, 0=RJ11,RJ41,RJ45,1=RJ12,RJ13
        │ │ │ │ │ │ └───── unused
        │ │ │ │ │ └────── CTS state,  0=follows RTS, 1=forced on
        │ │ │ └─┴─────── DTR modem behavior (see below)
        │ │ └────────── DCD, 0=forced on, 1=follows carrier
        │ └─────────── DSR, 0=forced on, 1=behaves normally
        └──────────── long space disconnect,0=disabled,1=enabled

       Bits
        43  DTR Modem Behavior Bits
        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


       │7│6│5│4│3│2│1│0│  S22   option status
        │ │ │ │ │ │ └─┴──── speaker volume, 01=low,10=med,11=high
        │ │ │ │ └─┴─────── speaker setting (see below)
        │ └─┴─┴────────── X command in effect
        └─────────────── make/break ratio, 0=39/61, 1=33/67

       Bits
        32  S22 Speaker Setting
        00  speaker always off
        01  speaker on until carrier detected
        10  speaker always on
        11  speaker off during dialing, then on until CD

       Bits
       654  S22 X Command in Effect
       100  X1 command in effect
       101  X2 command in effect
       110  X3 command in effect
       111  X4 command in effect


       │7│6│5│4│3│2│1│0│  S23   option status
        │ │ │ │ │ │ │ └──── remote dig.loop request,0=denied,1=ok
        │ │ │ │ │ └─┴───── baud rate (see table)
        │ │ │ │ └──────── unused
        │ │ └─┴───────── parity (see table)
        └─┴──────────── guard tone setting

       Bits
        21  S23 Baud Rate Table
        00  0-300 bps
        01  600 bps
        10  1200 bps
        11  2400 bps

       Bits
        54  S23 Parity Setting
        00  even parity
        01  parity bit always 0
        10  odd parity
        11  parity bit always 1

       Bits
        76  S23 Guard Tone Setting
        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 milliseconds (1)

       │7│6│5│4│3│2│1│0│  S27   option status
        │ │ │ │ │ │ └─┴──── synch/async mode (see table)
        │ │ │ │ │ └─────── phone line, 0= public, 1=leased
        │ │ │ │ └──────── unused
        │ │ └─┴───────── clock type (see table)
        │ └──────────── protocol, 0=CCITT V.22, 1=Bell 212A
        └───────────── unused

       Bits
        10  S27 Sync/Async mode
        00  asynchronous mode
        01  async/sync mode
        10  sync auto-dial
        11  sync manual dial

       Bits
        45  S27 Clock Type
        00  internal clock used
        01  external clock used
        10  slaved clock used

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