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Command/Response Reference Section 7-3
TCP Socket Number
(Command)
The TCP socket number to be opened specified as 1 byte between 1 and 8.
Results Storage Area
(Command)
The area in which the results of the command execution are stored. The first
byte specifies the memory area and data type (variable type). The 2nd to 4th
bytes specify the beginning address of the results storage area. Refer to
page 158 for details about the variable types and addresses that can be spec-
ified.
Local TCP Port Number
(Command)
The TCP port number for communications with the socket is specified as 2
bytes (0 cannot be specified).
The following ports used for the Ethernet Unit's communications services can-
not be specified.
• TCP port No. used for FTP server (Default: 20, 21)
• TCP port No. used for DNS server access (Default: 53)
• TCP port No. used for SMTP server access (Default: 25)
• TCP port No. used for POP server access (Default: 110)
• TCP port No. used for HTTP server (Default: 80)
Timeout Value (Command) The maximum control time between receiving the open request and storing
the result. If this set time limit is exceeded, the code for a timeout error will be
set as the results storage response code. The value is set in units of 0.1 s.
The timeout time is unlimited if the value is set to 0.
Remote IP Address
(Command, Results
Storage Area)
Specify the remote node’s IP address. If all zeroes are set, no remote node is
specified and connection is awaited from any node. If any other value is set,
connection is awaited from the specified remote node. The IP address of the
connected remote node will be stored in the results storage area.
Remote Port Number
(Command, Results
Storage Area)
Specify the remote TCP port number with this command. If all zeroes are set,
no remote TCP port number is specified. If any other value is set, it specifies
the TCP port number of the remote node. The TCP port number of the con-
nected remote node will be stored in the results storage area.
Precautions
Processing varies as shown in the table below according to the specified com-
bination of remote IP address and remote TCP port number.
70Bits
Keep-alive specification
0: Keep-alive disabled
1: Keep-alive enabled
Remote IP address Remote TCP port Description
0 0 All connection requests received
0 Not 0 Received only when port number
matches.
Not 0 0 Received only when IP address
matches.
Not 0 Not 0 Received only when IP address and
port number matches.
