User's Manual

HAYES AT COMPATIBLE COMMAND SET

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234839, Revision 2.2

AT&D Controlling Data Terminal Ready

DTR is an RS-232 signal used to indicate to the modem whether your local computer is ready to

communicate. The &D command is used to tell the modem how it will react when the DTR

signal goes low.

Command Description

AT&D0 The modem ignores the DTR signal and acts as if it is asserted (the modem assumes the

computer is ready to communicate).

AT&D1 If DTR is lowered, the modem returns to local command state (as if an escape sequence has

been typed).

AT&D2 The modem hangs up, returns to local command state if DTR has been asserted (high) and

then goes low (transition).

AT&D3 The modem hangs up, returns to local command state whenever DTR goes low. The modem

with this configuration must have DTR asserted before dialing or answering or an immediate

hang-up may occur.

AT&F Restore Factory Defaults

Your modem comes with factory default settings for all communications settings and S Registers.

The &F command enables you to restore the factory default values.

You must use the &W command if you wish to save the factory default values to non-volatile

memory, and thus preserve these values when you switch the modem off.

Command Description

AT&F0 Restore basic modem interface to factory defaults.

AT&F1 Restore radio and modem interface to factory defaults.