SENA PS400 - Manual (Page 34)

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or when no data transfer activity is found through the serial port for certain amount of time, which
is “Inactivity timeout” (See Options in section 4.4 for details on Inactivity timeout). All the data
remained in the serial port buffer will be cleared when it is disconnected.
Connection request from remote host
All the incoming TCP connection requests will be rejected in TCP client mode.
Cyclic Connection
It Cyclic Connection function is enabled, the HelloDevice Pro Series will make an attempt to
connect to the user-defined remote host at certain interval even if there’s no incoming serial data
from the device. If the remote host prepares certain data, it will be transferred to the serial device
via its serial port after the connection is established. Eventually, users can monitor the serial
device periodically by making the remote host send the serial command to the HelloDevice Pro
Series whenever it is connected to the remote host. This option is useful when users need to
gather the device information periodically even if the serial device does not send its data
periodically. Figure 4-6 shows the State Transition Diagram of the session operations in TCP client
mode.
Established
Closed
Data
Incoming data via
serial port
Inactivity time-out
TCP connection request rejected
Or
internal TCP timer is expired
TCP connection request accepted
Sync-Sent
Incoming data via
serial port
Incoming data
from remote host
Incoming TCP
disconnection request
Cyclic connection
interval time -out
Figure 4-6. State Transition Diagram of TCP client mode