Configuration and operation 
  6.9 Interface in the user program 
CP 443-1 Advanced (GX30) 
Manual, 03/2019, C79000-G8976-C256-05 
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Programmed communications connections - assigning parameters to the ports 
The CP now supports the following settings when assigning parameters to the ports in the 
parameter block for TCP connections and UDP connections: 
●  SUB_LOC_PORT parameter 
The port can be specified as an option when the connection is established actively. 
●  SUB_REM_PORT parameter 
The port can be specified as an option when the connection is established passively. 
 
Open TCP/IP communication 
Use 
To allow the user program to exchange data with other TCP/IPcompliant communication 
partners, STEP 7 provides a UDT for the connection parameter assignment and four 
program blocks (FBs): 
●  UDT 65 "TCON_PAR" with the data structure for connection parameter assignment 
●  FB65 "TCON" for connection establishment 
●  FB66 "TDISCON" for connection termination 
●  FB63 "TSEND" for sending data 
●  FB64 "TRCV" for receiving data 
TCP/IP communication is connectionoriented. Data can be transmitted only when a 
connection has been established to the communications partner. The CPU can use several 
connections to a communications partner at the same time. 
The following protocol variants are supported: 
●  ISO on TCP according to RFC 1006 
Make the following parameter settings in the connection description (UDT 65): 
●  local_tsap_id: Byte 1 = 0xE0 (value mandatory for correct functionality) 
●  local_tsap_id: Byte 2 = rack/slot number 
●  remote_tsap_id: Byte 1 = 0xE0 (value mandatory for correct functionality) 
●  remote_tsap_id: Byte 2 = rack/slot number