Comtrol AT Command Set Rev A - Manual (Page 176)

AT Commands Reference Manual
Conexant 100722B
5-4
5.1.3 Serial Port Speed and Flow Control
During fax mode, the DTE-DCE port speed is 19200 bps.
The DCE provides a speed buffer of 1024 bytes and provides the DC1/DC3
(XON/XOFF) or RTS/CTS method of controlling the data into the buffer. This flow
control is controlled by the &K3 or &K4 command.
This method of data flow control is available only for DTE to DCE direction of data.
There is no provision for data flow control from DCE to DTE.
Data Stream Termination
The DCE exchanges streams of data with the DTE while executing data transfer
commands. These data streams use the termination described in Section 3.2/ISO 2111.
The ASCII <DLE> character (016) is used as a special character to shield special
characters. The <DLE><ETX> character pair (<106><003>) is used to mark the end of a
stream. The following patterns are used:
any data...<DLE><ETX> end of stream
any data...<DLE><DLE> single <DLE> in data
any data...<DLE><any byte> delete <DLE><any byte>
DTE to DCE Streams
The DCE filters the data stream from the DTE, and removes all character pairs beginning
with <DLE>. The DCE recognizes <DLE><ETX> as the stream terminator. The DCE
recognizes <DLE><DLE> and reinserts a single <DLE> in its place.
The DTE must filter stream data to the DCE, and insert extra <DLE> characters ahead of
data.
DCE to DTE Streams
The DTE must filter the data stream from the DCE, and remove all character pairs
beginning with <DLE>. The DTE must recognize <DLE><ETX> as the stream
terminator. The DTE must recognize <DLE><DLE> and reinsert a single <DLE> in its
place.
The DCE filters stream data to the DTE, and inserts extra <DLE> characters ahead of
data.
5.1.4 Auto Answer
The DCE can answer as a data DCE or as a fax DCE. It can answer the call adaptively,
i.e., it can determine whether the call is 'data' or 'fax'. The +FAA parameter controls this
feature. Fax adaptive answer operates only when +FCLASS=0.
AT+FAA=1 ; Auto answer as a facsimile or a data modem depending on
the call
CONNECT XXXX ; DCE status response if data call
+FCON ; DCE status response if fax call