Intel MD566X manual For data mode

56K V.92 Data, Fax, and Voice Chipset

Table 3-4. Data Mode Command Descriptions (Continued)

DTR (Data Terminal Ready) Option: This command controls how the mo- dem responds to DTR. After toggling DTR, the host should wait 200 ms be- fore modifying the UART registers or sending a new command to the mo- dem. This is done because the modem does not send an “OK” message to indicate it has performed the requested function.

&Dn	2	n = 0	In asynchronous mode (&Q0), the modem ignores DTR.
		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-ini-
			tialize procedure performs the same function as a power-up reset,
			except that the UART registers are not reconfigured.
		Load Factory Defaults: This command loads command defaults and S-reg-
&F	none	ister 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
&Gn	0	tones are sent by the answer modem to disable Central Office echo cancel-
		ers.
		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. Bidirection-
&Kn	3	al hardware flow control uses RTS/CTS to stop and 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
		Select Communication Mode: This command controls whether the modem
		operates in asynchronous or synchronous mode. This modem only supports
&M0	0	asynchronous mode. This command is the same as &Q0.
		n = 0**	Asynchronous normal. The modem operates asynchronously in
			both command and online modes.

Programmer’s Guide Intel Confidential 51