Intel MD566X manual IS-101 Voice Mode AT Commands, Each command may be used as follows

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

6. IS-101 VOICE MODE AT COMMANDS

The 56K FastPath chipsets implement a voice mode AT command set that allows a DTE to record and play back voice messages. In addition to this programmer’s guide, the Intel IS-101 Voice Application Note, shows a number of ways to use these AT commands. This product is compatible with the EIA/TIA IS-101 voice command set. This section lists supported commands and a detailed description of each command (see Table 6-1 on page 82). When multiple commands are placed on a line, a semicolon (;) must be placed after each voice (and fax) command.

See Table 2-6and Table 2-7 on page 19 for voice character pairs (DTE-to-DCE and DCE-to-DTE).

Note: To originate a call, to answer, and to hang up, use the ATD, AT+VLS≠0, and AT+VLS=0 commands, respectively.

Each command may be used as follows:
+V<command>?	Read current setting
+V<command> = ?	Read permissible settings
+V<command> = <parameter>	Set parameter

For example, AT+FCLASS? determines whether the modem is configured for data (or fax) mode or voice mode. AT+FCLASS=? determines which data/fax/voice modes are supported by the modem. AT+FCLASS=n switches between voice mode and data mode.

The modem exchanges streams of data with the DTE while executing the commands for voice playback (AT+VTX) and record (AT+VRX) and while in voice command mode (with either the modem being off-hook or using the local phone — AT+VLS=n). In these modes, the DCE searches for DTMF, calling tone, and dial tones and reports them to the DTE whenever they are detected. Detection information and data stream terminators are passed between the DTE and DCE by first sending an ASCII <DLE> character ($10h) followed by a special character. Special characters in the data stream are used as follows:

any data ... <DLE><ETX>

any data ... <DLE><DLE>

any data ... <DLE><X> delete both <DLE> and X from the data stream

end of data stream ($10 $03)

single $10 in data stream

X is a special character,

When the DTE transfers data to the modem during playback mode (AT+VTX command), the DTE must insert a <DLE> for each <DLE> in the original data stream. When data is no longer available, the DTE must add the stream terminator <DLE><ETX> to the end of the data stream. If the modem detects the two terminating characters <DLE><ETX> within the data stream, it transmits the data immediately to the remote modem without waiting for the buffer to fill up. To abort playback mode without waiting for the modem to empty the internal modem buffer, send <DLE><CAN><DLE><ETX>. Immediately aborting the playback mode eliminates long delays between receiving a DTMF tone or keyboard abort and starting a new function such as playing back or recording a new message.

When the modem transfers data to the DTE during record mode (AT+VRX command), the DTE must filter the data stream by removing all character pairs beginning with <DLE>. The DTE also must recognize <DLE><ETX> as the stream terminator. Upon detecting <DLE><DLE>, the DTE must reinsert a single <DLE> in its place. The modem buffers up to 512 bytes of voice data received from the SAFE analog-to-digital converters if the DTE cannot read the data immediately.

80 Intel Confidential Programmer’s Guide