Extended AT command set

Command Description
AT&A0 Originate/Answer Mode Selection: Enables answer mode
AT&A1 Originate/Answer Mode Selection: Disables answer mode
AT&B0 Auto-Retrain Detection: Disable auto-retrain (modem hangs up)
AT&B1 Auto-Retrain Detection: Enable auto-retrain
AT&B2 Auto-Retrain Detection: Enable auto-retrain
AT&C0 DCD Option: DCD always enabled
AT&C1 DCD Option: DCD enabled after a carrier signal is detected
AT&D0 Modem Response to DTR Option: DTR is assumed to be on
AT&D1 Modem Response to DTR Option: DTR drop causes the modem back to command mode, but does not drop
AT&D2 Modem Response to DTR Option: DTR drop causes modem to hang up
AT&D3 Modem Response to DTR Option: DTR drop causes the modem to be reinitialized
AT&F0 Active Profile/Factory Defaults: Default profile #1 (Works with many modems)
AT&F1 Active Profile/Factory Defaults: Default profile #2 (Works with many modems)
AT&F2 Active Profile/Factory Defaults: Default profile #3 (Works with many modems)
AT&F3 Active Profile/Factory Defaults: Default profile #4 (Works with many modems)
AT&G0 Guard Tone Option: Guard tone is disabled
AT&G1 Guard Tone Option: A 550 Hz guard tone is enabled
AT&G2 Guard Tone Option: A 1800 Hz guard tone is enabled
AT&J0 Jack Type Selection: Selects RJ-11, RJ-41s, or RJ45s
AT&J1 Jack Type Selection: Selects RJ-12 or RJ-13
AT&K0 Flow Control Selection: Flow control disabled
AT&K1 Flow Control Selection: Normally unused (deals with RTS/CTS)
AT&K2 Flow Control Selection: Normally unused (deals with XON/XOFF)
AT&K3 Flow Control Selection: Enable RTS/CTS flow control
AT&K4 Flow Control Selection: Enable XON/XOFF flow control
AT&K5 Flow Control Selection: Enable transparent XON/XOFF flow control
AT&K6 Flow Control Selection: Enable unidirectional XON/XOFF flow control
AT&L0 Line Type Selection: Selects public switched telephone network (normal dialup)
AT&L1 Line Type Selection: Selects leased line
AT&M0 Communication Mode Selection: Asynchronous
AT&M1 Communication Mode Selection: Synchronous connect mode, asynchronous offline command mode
AT&M2 Communication Mode Selection: Synchronous connect mode, asynchronous offline command mode (DTR set to high)
AT&M3 Communication Mode Selection: Synchronous connect mode
AT&P0 Make/Break Ratio for Pulse Dialing: North America: Selects 39%-61% make/break ratio at 10 pulses per second
AT&P1 Make/Break Ratio for Pulse Dialing: Europe: Selects 33%-67% make/break ratio at 10 pulses per second
AT&P2 Make/Break Ratio for Pulse Dialing: Selects 39%-61% make/break ratio at 20 pulses per second
AT&P3 Make/Break Ratio for Pulse Dialing: Selects 33%-67% make/break ratio at 20 pulses per second
AT&Q0 Communications Mode Option Selection: Asynchronous mode, the serial port speed will follow the connection speed
AT&Q1 Communications Mode Option Selection: Asynchronous off-line command mode, synchronous connect mode
AT&Q2 Communications Mode Option Selection: Asynchronous off-line command mode, synchronous connect mode (this option will also have the modem the first number in its directory)
AT&Q3 Communications Mode Option Selection: Asynchronous off-line command mode (low DTR), synchronous connect mode (high DTR)
AT&Q4 Communications Mode Option Selection: Auto-synchronous mode
AT&Q5 Communications Mode Option Selection: Error correction mode
AT&Q6 Communications Mode Option Selection: Buffered asynchronous mode
AT&Q8 Communications Mode Option Selection: Enables Microcom Networking Protocol (MNP) error control mode.
AT&Q9 Communications Mode Option Selection: V.42 or MNP error control mode.
AT&R0 RTS/CTS Option Selection:
AT&R1 RTS/CTS Option Selection:
AT&S0 DSR Option Selection: Force DSR high
AT&S1 DSR Option Selection: Force DSR high during handshake and connection
AT&S2 DSR Option Selection: Force DSR high will connected
AT&T0 Test Option Selection: End test
AT&T1 Test Option Selection: Begin a local analog loopback test
AT&T3 Test Option Selection: Begin a local digital loopback test
AT&T4 Test Option Selection: Allow a remote digital loopback test
AT&T5 Test Option Selection: Disallow a remote digital loopback test
AT&T6 Test Option Selection: Request a remote digital loopback test
AT&T7 Test Option Selection: Request a remote digital loopback test and a self test
AT&T8 Test Option Selection: Start a local analog loopback and self test
AT&U0 Trellis code modulation
AT&U1 Trellis code modulation
AT&V0 Display Current configuration and profile
AT&V1 S Registers Display
AT&W0 Active Profile Write: Write active profile into stored profile 0
AT&W1 Active Profile Write: Write active profile into stored profile 1
AT&X0 DTE Transmit Clock Source: Modem
AT&X1 DTE Transmit Clock Source: DTE
AT&X2 DTE Transmit Clock Source: Modem generates the clock with regards to the receiving carrier signal
AT&Y0 Active Profile Read: Restore from stored profile 0
AT&Y1 Active Profile Read: Restore from stored profile 1
AT&Zn=x Telephone Number Write