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11-3
Section
Command/Response Reference
204
11-3-13
PASSIVE TCP OPEN REQUEST
Requests processing to open a TCP socket. The socket will wait to be connected
to another node.
Command Block
10
27
Command
code
TCP
socket
number
Results storage area
Local
TCP
port
number
Timeout
value
Remote IP
address
Remote TCP
port number
Response Block
10
27
Command
code
Response
code
Results Storage Format
Response
code
Remote IP
address
Remote port
number
Parameters
The TCP socket number to be opened specified as 2 bytes between 1 and 8.
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 192 for
details about the variable types and addresses that can be specified.
The TCP port number for communications with the socket is specified as 2 bytes
(0 cannot be specified). Do not specify the port number of the FTP server (port
#21).
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.
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, con-
nection is awaited from the specified remote node. The IP address of the con-
nected remote node will be stored in the 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 connected
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.
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.
TCP Socket Number
(Command)
Results Storage Area
(Command)
Local TCP Port Number
(Command, Results
Storage Area)
Remote IP Address
(Command, Results
Storage Area)
Remote Port Number
(Command, Results
Storage Area)