56K V.92 Data, Fax, and Voice Chipset
Programmer’s Guide Intel Confidential 73
5.2 Fax Clas s 1 Commands
The fax Class 1 AT commands are divided into three types: class selection and capabilities, data
stream transfers, and silence-time timers. All fax mode commands, except the silence-time timers,
must be the last command on the command line.
Each command may be used as follows:
+F<command>? Reads current setting
+F<command> = ? Reads permissible settings
+F<command> = <parameter> Sets parameters
NOTE: To originate a call, answer, and hang up, use the ATD, ATA, and ATHn
commands, respectively.
The fax AT+FCLASS command is used for changing between fax classes, determining the current
class selection, and determining the supported fax classes. Both data/fax Class 0 (data modem
mode) and Class 1 (fax modem mode) are implemented by the modem. In Class 0, the DTE-to-
modem data rate can be set from 300 bps to 115,200bps. In Class 1, it is recommended that the
DTE-to-modem data rate is set to 19,200 bps.
The silence-time timers consist of AT+ FTS=<T IME> and AT+FRS=<TIME>. Silence time is
defined as the length of time when the modem neither receives nor transmits energy (that is,
modem transmit carrier) on the telephone line.
The modem exchanges streams of data with the DTE while executing the data transfer commands
AT+FTM=<mod>, AT+FTH=<mod>, AT+F RM=<m od>, and AT+FRH=<mod>. The values
supported for <mod> are provided in Table 5- 2.
During data transfer, an ASCII <DLE> character ($10h) is used as a special character to shield
other special characters.
Special characters in the data stream are used in the following way:
any data ... <DLE><ETX> end of data stream
any data ... <DLE><DLE> single $10 in data str eam
any data ... <DLE>
<not DLE or ETX> delete both <DLE> and next character
When the DTE transfers data to the modem, the DTE must insert a <DLE> for each <DLE> in the
original data stream. In addition, when data is no longer available, the DTE must add the stream
terminator <DLE><ETX> to the end of the data stream. The modem buffers up to one thousand
+FREV?/+FMR? none
Identifies Product Version Number: This command causes the DCE to report
the modem chipset revision level. This command is iden tical to ATI1 and
AT+G MR?.
AT+FREV?
CD08.55-612 (10/19/99) PARALLEL-SPEAKER PHONE 05
OK

Table 5-1. Fax Identity Command Descriptions