User guide
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internal buffer. The Pro Series transfers data stored in the buffer via TCP/IP, only if the internal
buffer is full or if the inter-character time interval reaches the time specified in the inter-character
timeout setting. If inter-character timeout is set as 0, then data stored in the internal buffer will be
transferred immediately without any delay.
Optimal inter-character timeout would be different according to your application but at least it must
be larger than one character interval within specified baud rate. For example, assume that the
serial port is set to 1200 bps, 8 Data bits, 1 stop bit, and no parity. In this case, the total number of
bits to send a character is 10 bits and the time required to transfer one character is
10 (bits) / 1200 (bits/s) * 1000 (ms/s) = 8.3 ms.
Therefore, you have to set inter-character timeout to be larger than 8.3 ms. The inter-character
timeout is specified in milliseconds.
4.2.7. Modem configuration
The Pro Series supports direct modem connection to the serial port. When user wants to connect to a
modem on its serial port, he must configure Modem init-string and DCD behavior on the modem
configuration page. The Pro Series supports modem connection only when host mode is set as TCP
mode.
Enable/Disable modem
By enabling this menu, user can attach a modem directly to the serial port of Pro Series. If this
parameter is enabled, Pro Series considers this port will be used for modem use exclusively.
Modem init-string
User can specify modem initialization string for his modem in Modem init-string parameter. When
a serial port is set to modem mode by setting Enable/Disable modem parameter as Enabled, Pro
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