Specifications

Chapter 3 – Fax Class 2 Commands
Multi-Tech Systems, Inc. SocketModem MT5600SMI/MT5656SMI Reference Guide (S000306B) 82
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.
Command: +FDT Data Transmission
Syntax: +FDT <CR>
The +FDT command prefixes Phase C data transmission. When the DCE is ready to accept Phase C
data, it issues the negotiation responses and the CONNECT result code to the DTE.
In Phase B, the +FDT command releases the DCE to proceed with negotiation, and releases the DCS
message to the remote station. In Phase C, the +FDT command resumes transmission after the end of a
prior transmit data stream.
Initiate Page Transmission
Phase B DCE polled response:
[+FCSI:<remote ID string>] - if new CSI received
[+FDIS:<subparameters from remote station>] - if new DIS received
+FDCS:<T.30 subparameter string>
CONNECT
<XON> - when ready for data
After placing a call, or after finishing a document exchange, the DTE may command the DCE to re-enter
T.30 Phase B to attempt to negotiate a document transmission.
Continue a Page
CONNECT
<XON>
The DTE may issue more than one +FDT command for a given page, so that different files may be
concatenated together. These files must have the same format.
Phase C Data Framing
Phase C data must be presented to the DCE in stream mode. The DCE expects Phase C data to follow
until it detects <DLE><ETX> termination characters. The DCE will filter the stream.
The DCE will acknowledge the end of the data by returning the OK result code to the DTE.
If there is data underrun before the next +FDT or +FET= command, the DCE will zero-fill the pad as per
T.4 until the Phase C timeout (+FPHCTO) is reached, or until more data is received. The DCE appends
an RTC pattern to the transmit data after an +FET= command is received from the DTE.
Phase C Data Format
The Phase C data will be of the format specified by the negotiated T.30 DCS frame.
The DCE will use the negotiated minimum Scan Time parameter from the DCS frame, and insert
sufficient fill bits to pad each line to the minimum scan time. This is reported in the +FDCS:ST
subparameter.