Intel MD566X manual Establishing a Modem Connection A, D, DS = n, S0

	56K V.92 Data, Fax, and Voice Chipset
ATI1	Causes the modem to send the modem’s firmware
	version to the DTE.

CD08.55-612 (10/19/99)PARALLEL-SPEAKERPHONE 05-DSP PATCH.001.55

Firmware version that is the modem’s response to the command.

3.5 Establishing a Modem Connection [A, D, DS = n, S0]

Data mode provides several methods for establishing a connection with a remote modem. For each modem, a connection can be initiated manually or automatically in both answer and originate modes. A manual-to-manual connection is useful when both modems (that are on-hook) are connected to an off-hook telephone line. For example, if two people are talking on the telephone, they can manually establish a modem connection without first hanging up. When establishing a manual connection, one modem must be designated as the originating modem and the other as the answering modem. Manual originate mode is initiated by sending an ATD to the DCE. Manual answer mode is accomplished by sending an ATA to the DCE.

Automatic originate mode is initiated by sending an ATD <telephone number & dial modifiers> or ATDS=n to the DCE. Automatic-answer mode is accomplished by setting S-register S0 to a non-zero value. S1 keeps track of how many ring signals are detected. If the content of S0 is non- zero and the number of ring signals (as defined by S0) are detected (that is, S1 = S0), then the DCE goes off-hook and attempts to connect to the remote modem (with the following exceptions):

1)The time period between the ring signals is greater than 8 seconds, which causes the S1 counter to reset and thus never reach the value for S0.

2)Caller ID is enabled and S0=1, the modem answers on the second ring signal instead of the first ring signal. This happens because Caller ID puts a signal on the telephone line between the first and second ring signal.

Example:
ATDT9,444-5555	Automatically dials the telephone number with
	DTMF tones. After dialing a “9”, the comma (,)
	causes the modem to pause two seconds before
	dialing the rest of the telephone number.
modem 1: ATD;	When establishing a manual-to-manual connection,
	the designated originating
modem 2: ATA	modem should receive the ATD command from its
	DTE just before the designated answering modem
	receives the ATA command from its DTE.
	It is important that the time between the ATD and
	ATA commands is less than 2 seconds.
AT-C1DT 123	Causes the modem to dial the telephone number 123
	and immediately start sending a data calling tone.
	Calling tone can then be detected by the remote voice
	mail system. After detecting the calling tone, the
	remote system can change to data mode and start the
	data modem connection handshake.

Programmer’s Guide Intel Confidential 27