Synxcom SM9234D, User Manual

Page: 174 / 216

AT Commands
Page 174
ATA - Answer a Call
The DCE can support a DTE command to answer an incoming call using the ATA
command.
The DTE may issue an Answer command in response to an incoming ring.
If the Answer command is unsuccessful, the DCE will report an appropriate failure
or error type result code, such as NO CARRIER.
Manual Call Answer
If this call is successful, the typical DCE response (answer and receive) is:
+FCON
[+FTSI:<remote ID string>]
+FDCS:<T.30 subparameter string>
OK
(DTE should issue +FDR command here)
Upon receipt of an Answer command from the DTE, the DCE answers and
generates the CED tone. The DCE then generates a DIS frame (derived from the
+FDIS parameter) and hunts for the first T.30 negotiation frames. Upon detection
of the first Phase B preamble (V.21 ch 2 modulated by 300 bps HDLC flags), it
reports the “+FCON” message to the DTE.
The DTE should report the initial received T.30 negotiation messages, including
the DCS frame. The +FDCS: report will be followed by the OK final result code.
Automatic Answer
The modem provides for automatic answering of incoming calls. If configured for
automatic answer, the modem answers an incoming call in compliance with T.30,
and reports the same messages as described for manual answer.
Connection as a Data Modem
If configured to do so by the +FAA parameter, the DCE will adaptively answer as
a facsimile DCE or as a data DCE. If the DCE answers as a data DCE, it resets the
+FCLASS parameter to 0 and issues the appropriate final result code (e.g.,
CONNECT, or NO CARRIER) to the DTE.