Standard Hayes Compatible AT Command Set

Section 2

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Bolded text indicates default setting (&F)


Forces RSLD (DCD) on

RLSD (DCD) follows remote carrier




DTR is assumed on. Allows operation with DTE's that do not provide DTR signal

Modem interprets DTR drop as if it received the escape sequence. Returns to command mode without disconnecting.

DTR drop causes modem to hang up. Auto-answer is inhibited.

DTR drop causes modem to do soft reset. &Y setting determines which profile is loaded.

Loads factory default settings.


Disables guard tone

Disables guard tone

Enables 1800 HZ guard tone





Disables flow control

Enables RTS/CTS (hardware) flow control

Enables XON/XOF (software) flow control

XON/XOFF with passthrough

Enables both RTS/CTS and XON/XOFF

Selects asynchronous mode (&Q0)

Make/break dial ratio of 39/61 at 10 PPS

Command accepted but not acted upon



Selects direct asynchronous mode (no error correction) or speed buffering

Modem negotiates error-correcting connection

Selects asynchronous mode with speed buffering (no error correction)


Forces Data Set Ready (DSR) signal on continuously

DSR active after answer tone detected and inactive after carrier loss










For engineering test purposes only

Ends test in progress

Starts local analog loopback test

Returns error

Starts local digital loopback test

Responds to remote modem request for digital loopback

Ignores remote modem request for digital loopback

Requests remote digital loopback without self-test

Same as &T6 with self-test

Starts local analog loopback with self-test.

Displays the current (active) and stored profiles and stored numbers

Saves active configuration as profile 0

Saves active configuration as profile 1


Modem uses profile 0 on power up (See &W0)

Modem uses profile 1 on power up (See &W1)

Stores telephone number (up to 35 digits) in non volatile memory location n (0-3)