SENA PS810 - Manual (Page 47)

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protecting the Internet against excessive packet loads. However, some applications suffer
performance problems as a result of the traditional implementation of the Nagle algorithm.(An
interaction between the Nagle algorithm and TCP’s delayed acknowledgement policy can create
especially severe problems, through a temporary “deadlock.”) TCP Nagle algorithm can be disabled or
enabled through this option.
 DTR/DSR behavior
Purpose of the DTR/DSR pin is to control TCP connection state by using serial port signal. The DTR is
a write-only output signal, whereas the DSR is a read-only input signal in the Pro Series.
The DTR option can be set to one of three options:
Always HIGH: The state of the DTR pin is maintained high.
Always LOW: The state of the DTR pin is maintained low.
High when TCP/UDP is opened: The state of the DTR pin will be maintained high if the TCP
connection is established.
The Allow incoming connection can be set to one of two options:
Always: Incoming connection from remote host is always allowed.
Only when DSR is high: Incoming TCP connection from remote host is allowed only when the
state of DSR pin is high.
The When DSR goes low can be set to one of two options:
Do nothing: Nothing is done when the state of DSR pin becomes low from high.
Close all connections: All the TCP connections are closed when the state of DSR pin becomes
low from high.
The When DSR goes high can be set to one of three options:
Do nothing: Nothing is done when the state of DSR pin becomes high from low.
Try to connect continuously: Pro Series continuously tries to establish the connection to remote
host when the state of DSR pin becomes high from low.
Try to connect once: Pro Series only once tries to establish the connection to remote host when
the state of DSR pin becomes high from low.
Note:
1. DTR/DSR behavior configuration will not be effective when the modem is enabled.
2. DTR/DSR behavior is not effective in RS422 and RS485 mode.