Intel manual Intel Confidential, Data Mode AT COMMANDS, 536EX Chipset Developer’s Manual

Data Mode AT COMMANDS

Table 18. Data Mode Command Descriptions (Continued)

Command	Default		Description
		Long Space Disconnect: This command determines whether the modem disconnects after receiving
		1.6 seconds of silence and whether the modem sends a period of silence to the remote modem before
		disconnecting.
Yn	0	n = 0*	Disables long space disconnect
		n = 1	Enables long space disconnect. The modem disconnects after receiving 1.6 seconds of
			silence from the remote modem. Additionally, after receiving an ATH0 command, the
			modem sends at least 4 seconds of silence before hanging up.
		Reset Modem/Recall Stored Profile: This command causes the modem to go on-hook (hang-up),
		perform a warm reset, and load user-configuration profile ‘n’ (previously stored in the NVRAM) into the
Zn	0	active profile. The Zn command must be the last command in command string, as it causes all
		subsequent commands to be ignored.
		n = 0*	Resets the modem and recalls user profile 0
		n = 1	Resets the modem and recalls user profile 1
		DCD (Data Carrier Detect) Option: This command controls how the modem functions in relation to the
		DCD or RLSD signal.
&Cn	1	n = 0	State of carrier from remote modem is ignored. DCD is always on.
		n = 1*	State of carrier from remote modem is tracked. DCD reflects the state of the received
			carrier.
		DTR (Data Terminal Ready) Option: This command controls how the modem responds to DTR. After
		toggling DTR, the host should wait 200 ms before modifying the UART registers or sending a new
		command to the modem. This is done because the modem does not send an ‘OK’ message to indicate it
		has performed the requested function.
		n = 0	In asynchronous mode (&Q0), the modem ignores DTR.
&Dn	2	n = 1	The modem switches from data mode to command mode when an on-to-off transition of
			DTR occurs.
		n = 2*	An on-to-off transition of DTR causes the modem to go on-hook (hang up). While DTR is
			off, auto-answer is disabled.
		n = 3	An on-to-off transition of DTR re-initializes the modem. The re-initialize procedure performs
			the same function as a power-up reset, except that the UART registers are not
			reconfigured.
&F	none	Load Factory Defaults: This command loads command defaults and S-register factory defaults into the
		active configuration and configures the modem for data mode.
		Guard Tone Option: This command controls whether the modem sends out guard tones while
		connected to a remote modem (for ITU-T V.22 bis [1200 bps] and V.22 bis [2400 bps] connections only).
		Guard tones may be required in some countries but are not needed in the United States. Guard tones are
&Gn	0	sent by the answer modem to disable Central Office echo cancelers.
		n = 0*	Guard tone disabled
		n = 1	550 Hz guard tone enabled
		n = 2	1800 Hz guard tone enabled
		Select Serial Port Flow Control: This command specifies the DTE-to-modem flow control. Software
		flow control uses the characters XOFF (13h) and XON (11h) to stop and start data transmission,
		respectively, both to and from the DTE. Bidirectional hardware flow control uses RTS/CTS to stop and
&Kn	3	start data from the modem.
		n = 0	Disables flow control
		n = 3*	Bidirectional hardware flow control—RTS/CTS
		n = 4	XON/XOFF software flow control

NOTE: An asterisk (*) denotes the factory-default setting.

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