User`s manual

NPort 6000 Series User’s Manual Configuring Serial Port Operation Modes
7-19
Ethernet Modem Mode
The NPort 6000 accepts the AT command ATD IP address:TCP port (for example, ATD
192.127.168.1:4001) from the serial port and then requests a TCP connection from the remote
Ethernet Modem or PC. Here IP address is the IP address of the remote Ethernet modem or PC,
and TCP port is the TCP port number of the remote Ethernet modem or PC. Once the remote unit
accepts this TCP connection, the NPort 6000 will send out the “CONNECT baud” signal via the
serial port and then enter data mode.
TCP alive check time (default=7 min): This field specifies how long the NPort 6000 will wait for
a response to “keep alive” packets before closing the TCP connection. The NPort 6000 checks
connection status by sending periodic “keep alive” packets. If the remote host does not respond to
the packet within the time specified in this field, the NPort 6000 will force the existing TCP
connection to close. For socket and device control modes, the NPort 6000 will listen for another
TCP connection from another host after closing the connection. If TCP alive check time is set to 0,
the TCP connection will remain open even if there is no response to the “keep alive” packets.
TCP port (default=4001): This is the TCP port number assignment for the serial port on the NPort
6000. It is the port number that the serial port uses to listen to connections, and that other devices
must use to contact the serial port. To avoid conflicts with well known TCP ports, the default is set
to 4001.
Dial-in
The NPort 6000 listens for a TCP/IP connection request from the remote Ethernet modem or host.
The NPort 6000’s response depends on the ATS0 value, as follows.
ATS0=0:
The NPort 6000 will temporarily accept the TCP connection and then send the “RING” signal out
through the serial port. The serial controller must reply with “ATA” within 2.5 seconds to accept
the connection request, after which the NPort 6000 enters data mode. If no “ATA” command is
received, the NPort 6000 will disconnect after sending three “RING” signals.
ATS0≧1:
The NPort 6000 will accept the TCP connection immediately and then send the “CONNECT
baud” command to the serial port, in which baud represents the baudrate of the NPort 6000’s serial
port. After that, the NPort 6000 immediately enters data mode.