Intel 536EX manual 6.1DTMF Detection Reporting, 6.2Relay Control, Intel Confidential

IS-101 Voice Mode AT Commands

6.1DTMF Detection Reporting

DTMF detection information is reported by the modem to the DTE by a <DLE> shielded command as outlined in Section 6.5 of the ITU V.253 specification. When the DTMF burst is detected in Voice mode, the modem sends to the DTE a <DLE></> followed by a sequence of <DLE><-> is inserted to indicate the end of the determination interval.

For example, a single 280ms burst of DTMF 5 would report:

<DLE></><DLE><5><DLE><5><DLE><5><DLE><5><DLE><->

6.2Relay Control

To originate a call (that is, to originate call forwarding or auto-dialing) and to generate tones, use the dialing command:

ATDT <telephone number>

If the modem was not already off-hook, then this command automatically configures the value for AT+VLS=m to m = 1 or m = 5 depending on the value for Mn.

To answer a call, use the AT+VLS=m command. Unlike data mode, the modem (when configured for voice mode) does not automatically answer an incoming call (that is, the modem ignores the contents of S-register S0).

Remote playback/record takes place whenever the modem is off-hook (OHREL* is activated). For local playback/record, the modem is on-hook, and the user uses a local telephone or handset. The LPHREL* relay driver may be used to control the local telephone or handset when implementing local playback/record mode (AT+VLS=m). Additionally, voice messages may be played through the modem/computer speaker. The 536EX chipsets also provide a microphone interface that can be used for local recording.

In voice mode, all voice AT commands can be issued by the DTE at any valid speed between 300 bps to 115,200 bps. Typically, the DTE-to-modem data rate is set for 19,200 bps, which is the recommended data rate for Class 1 fax mode. The DTE-to-modem data rate may need to be set to 115,200 bps in certain instances, such as during playback or during record mode for a CL1 compression scheme.

The following data and fax AT commands are supported in voice mode:

Data: All except ATA, ATIn

Fax: +FCLASS

Table 25. Voice Mode Command Descriptions

Command	Default		Description
		Voice Mode Selection: This command enables or disables voice mode. All voice mode commands
+FCLASS		(except for +FCLASS=m) are valid only in voice mode.
	0	0*	Data mode
=8
		1	Class 1 fax mode
		8	Voice mode enabled

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

536EX Chipset Developer’s Manual 71

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