SENA PS210W - Manual (Page 64)

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Series sends modem initialization string to the serial port whenever rising edge of DTR pin is
detected or parameter related with serial port configuration is changed.
 DCD behavior
If DCD behavior is set as Allow TCP connection only by HIGH, Pro Series permits a connection
from the remote host only when the DCD status of serial port is high. This feature is useful when
user want to use a serial port only for dial-in modem mode. In this case, if there is no connection
through modem already, Pro Series will not permit a TCP side connection.
 Automatic release modem connection
If Automatic release modem connection is set as Enable, modem connection will be closed by Pro
Series if all TCP connections are closed. If this option is set as Disable, modem connection will
not be closed by Pro Series even if all TCP connections are closed. Please note that actual phone
line connection will be closed if one of modems closes connection. That is, this option can be
used for Pro Series to allow disconnection of a modem connection by itself when all TCP
connections are closed.
If user wants to use dial-out function, he should set DCD behavior as None because he must be able
to access modem connected to a serial port to send dial out command to the modem first.
Figure 4-15 Modem configurati on