147
6 F 3 B 0 3 6 2
RCLOSE
CONN
8.4 Socket Interface Information
The information for the eight socket interface sockets held by the Ethernet Port can be read out
with the T2N READ instruction. (See Section 6.3 Socket Interface Information.) The Ethernet Port
holds five words of socket status information for each socket.
• Remote port TCP/UDP port number
• Remote port IP address
• TCP/UDP port number for this socket
• Socket status
Table 8.7 lists the structure of the socket interface information and the extended memory area
addresses.
Table 8.7 Socket Interface Information
Socket identifier
1 2 3 4 5 6 7 8
Remote port number (TCP only) 0F4BH 0F53H 0F5BH 0F63H 0F6BH 0F73H 0F7BH 0F83H
Remote port IP address (TCP only)
0F4DH
0F55H
0F5DH
0F65H
0F6DH
0F75H
0F7DH
0F85H
Local port TCP/UDP port number 0F4EH 0F56H 0F5EH 0F66H 0F6EH 0F76H 0F7EH 0F86H
Socket status 0F4FH 0F57H 0F5FH 0F67H 0F6FH 0F77H 0F7FH 0F87H
For UDP sockets, the remote port number and IP address data are invalid.
The socket status has the following structure.
F E D C B A 9 8 7 6 5 4 3 2 1 0
Bit no. Bit Condition under which the bit is set to 1 Condition under which the bit is reset to 0
F TCP TCP used by the socket The socket closed in response to a close request
E UDP UDP used by the socket The socket closed in response to a close request
D AOPEN TCP socket in active open state The socket closed in response to a close request
C POPEN
TCP socket in passive open state or UDP
socket in open state
The socket closed in response to a close request
B CONN TCP connection established Disconnected by the local port with a close request
Disconnected by the remote port
A RCV Received text present No received text
9
E
An established TCP connection disconnected
by the remote port
The socket closed in response to a close request
8 NOACK
No response received from the remote port for
a local port send operation in a state where a
TCP connection was established, and the TCP
resend function resulted in a timeout (because
the remote port was down, etc.).
The socket closed in response to a close request
If the wait time exceeds the set value during a
This state does not occur for TCP passive
open requests.
When a TCP active open request is reissued.
AOPEN
TCP
A socket status in which neither AOPEN nor POPEN is set to 1 indicates that the socket is in the
