The Hayes AT Modem Commands

This is a description of common modem AT commands.

General | Ampersand (&) | S Registers

Dial Commands

0-9 Digits to Dial
*   Auxiliary Tone Dial Digit
#   Auxiliary Tone Dial Digit
T   Tone Dialing
P   Pulse Dialing
R   Call an Originate Only Modem
,   Pause (Wait for S8 Time)
;   Remain in Command Mode After Dialing
"   Used to Dial Alpha Phone #'s
W   Wait for 2nd Dial Tone (X3-X7)
@   Wait for an Answer (X3-X7)
!   Flash Switch Hook
 

Ampersand Commands

&An;  n=0  Disable /ARQ Result Codes   &Pn;  n=0  N.American Pulse Dial       
      n=1  Enable /ARQ Result Codes          n=1  UK Pulse Dial               
      n=2  Enable /Modulation Codes    &Rn;  n=0  CTS Follows RTS             
      n=3  Enable /Extra Result Codes        n=1  Ignore RTS                  
&Bn;  n=0  Floating DTE Speed                n=2  RX to DTE/RTS high          
      n=1  Fixed DTE Speed             &Sn;  n=0  DSR Always On               
      n=2  DTE Speed Fixed When ARQ          n=1  Modem Controls DSR          
&Cn;  n=0  CD Always On                      n=2  Pulse DSR, CTS=CD           
      n=1  Modem Controls CD                 n=3  Pulse DSR                   
&Dn;  n=0  Ignore DTR                  &Tn;  n=0  End Test                    
      n=1  Reserved                          n=1  Analog Loopback (ALB)       
      n=2  DTE Controls DTR                  n=3  Digital Loopback (DLB)      
&F;   Load Factory Configuration             n=4  Grant Remote DLB            
&Gn;  n=0  No Guard Tone                     n=5  Deny Remote DLB             
      n=1  550 Hz Guard Tone                 n=6  Remote Digital Loopback     
      n=2  1800 Hz Guard Tone                n=7  Remote DLB With Self Test   
&Hn;  n=0  Disable TX Flow Control           n=8  ALB With Self Test          
      n=1  CTS                         &W;   Store Configuration              
      n=2  Xon/Xoff                    &Xn;  n=0  DCE Synchronous Clock       
 

S Register Functions

S0  Ring to Answer On                  S19 Inactivity Timeout (min)           
S1  Counts # of Rings                  S20 Reserved                           
S2  Escape Code Char                   S21 Break Length (1/100sec)            
S3  Carriage Return Char               S22 Xon Char                           
S4  Line Feed Char                     S23 Xoff Char                          
S5  Backspace Char                     S24 DSR Pulse Time (1/50sec)           
S6  Wait Time/Dial Tone (sec)          S25 Reserved                           
S7  Wait Time/Carrier (sec)            S26 RTS/CTS Delay Time (1/100sec)      
S8  Comma Time (sec)                   S27 Bit Mapped                         
S9  Carrier Detect Time (1/10sec)            1 = V21 Mode                     
S10 Carrier Loss Time (1/10sec)              2 = Disable TCM                  
S11 Dial Tone Spacing (msec)                 4 = Disable V32                  
S12 Escape Code Time (1/50sec)               8 = Disable 2100hz               
S13 Bit Mapped                              16 = Disable MNP Handshake        
      1 = Reset On DTR Loss                 32 = Disable V.42 Detect Phase   
      2 = Do Originate in Auto Answer       64 = Reserved                     
      4 = No Pause Before Result Codes     128 = Unusual SW-Incompatibility   
      8 = Do DS0 On DTR                S28 V32 Handshake Time (1/10sec)       
 

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URL: http://help.unc.edu/tac/vhd/peripherals/modem/hayes.html
Last modified: 10/30/97