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Flow control considerations – Sierra Wireless DART 200 CDPD Modem User Manual

Page 106

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DART 200 CDPD Modem User’s Guide

8 Application Programming

Sierra Wireless, Inc.

8-12

2. To use the ATA method, the MAS must have a device. Read

command is pending on the COM port and issues an ATA command
in response to the incoming Ring.
OR
S-Register 0 = 1 enables the DART 200 to remain permanently in
auto answer mode; making call answering fully automatic
(recommended, especially) when dealing with low intelligence
terminals not capable of issuing an ATA command.

3. To answer automatically set S-Register 0=1 enabling the DART to

remain permanently in auto answer mode; making call answering
fully automatic. This is the recommended method, especially when
dealing with low intelligence terminals not capable of issuing an
ATA command.

4. Completion of call establishment at the server in both TCP and UDP

modes of operation is indicated by a CONNECT message (verbose
mode) or 1 response (terse mode). This response can be suppressed,
if necessary, by putting the modem in Quiet Mode (ATQ1).

To set up the DART 200 server for auto answer, use the following
commands:

1. AT*An to activate the appropriate server (1 for TCP, 2 for UDP).
2. ATS0=1 to enable auto answer.
3. AT*Ln to set the listening port. Set the port number in the range

1025 to 4999 (default listening port is 2100 for backward
compatibility and can be left unchanged).

4. AT&W to save settings.

5. Incoming connection requests must reference the listening port. For

example, a TCP establishment request from another DART would be
ATDTn.n.n.n/2100.

This information applies for calls between DARTs, or for calls to a
DART when operating in TCP, UDP, or telnet modes of operation.

Flow control considerations

Flow control is used by a device receiving data over the RS-232 interface
to prevent the transmitting device from sending data faster than the
receiver can process it. The DART 200 supports hardware flow control,
Request to Send (RTS)/Clear to Send (CTS), and Software flow control,
XON/XOFF.

The DART 200 also operates without flow control, leaving you to ensure
that data overruns do not occur. This feature is specified by the \Qn
option; the default is \Q2 Hardware Flow Control.

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NOTE:
Flow control is only
active when in online
mode.