Chapter 2 - Fax Class 1 Commands; Fax I/O Processing; Dte-To-Modem Transmit Data Stream; Modem-To-Dte Receive Data Stream - Multitech SocketModem MT5600SMI Reference Manual

Chapter 2 – Fax Class 1 Commands

Fax I/O Processing

The fax I/O interface supports asynchronous serial and parallel interfaces. The character format is 8 bit
data, no parity, and 1 stop bit. Start and stop elements are removed from the transmit data and added to
the receive data. Both transmit and receive data are buffered. Flow control using XON/XOFF or RTS/CTS
is provided.
Unique control character strings are identified, filtered, or reinserted into the I/O data stream. These
control characters and their resultant action are described below.

DTE-to-Modem Transmit Data Stream

Characters Detected
<DLE><data>
<DLE><ETX>
<DLE><DLE>

Modem-to-DTE Receive Data Stream

Characters Detected
<DLE>
The modem also identifies the end of a frame by inserting <DLE><ETX> into the data stream after the
FCS bytes.
Multi-Tech Systems, Inc. SocketModem MT5600SMI/MT5656SMI Reference Guide (S000306C)
Action Taken
Delete <DLE><data> characters.
Recognize as a string terminator and take appropriate action.
Replace with single <DLE> character.
Action Taken
Insert extra <DLE> ahead of <DLE>.
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