Properties and services 
  1.3 Communication services 
CP 443-1 Advanced (GX30) 
Manual, 03/2019, C79000-G8976-C256-05 
17 
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Open communication services with the following functions:
 
–  SEND/RECEIVE interface over ISO transport connections 
–  SEND/RECEIVE interface over TCP connections, ISO-on-TCP and UDP connections 
With the SEND/RECEIVE interface via TCP connections, the CP supports the socket 
interface to TCP/IP available on practically every end system. 
UDP frame buffering on the CP can be disabled during configuration. When 
necessary, this allows you to achieve a shorter reaction time between the arrival of a 
UDP frame and its evaluation on the CPU. 
–  Multicast over UDP connection 
The multicast mode is made possible by selecting a suitable IP address when 
configuring connections. 
–  FETCH/WRITE services (server services; corresponding to S5 protocol) via ISO 
transport connections, ISO-on-TCP connections and TCP connections; 
Here, the SIMATIC S7400 with the CP is always the server (passive connection 
establishment) while the read or write access (client function with active connection 
establishment) is always initiated by a SIMATIC S5 or a device from another range / 
PC. 
–  LOCK/UNLOCK with FETCH/WRITE services (CPU-dependent; see section 
Requirements for use (Page 41)) 
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Open TCP/IP communication
 
Open TCP/IP communication provides a program interface for the transfer of connection-
oriented and connectionless services. The establishment and termination of connections 
is initiated here only via the "dynamic" program interface. 
STEP 7 provides a UDT for the connection description as well as four FBs for data 
exchange. 
The CP supports communication via ISO-on-TCP connections for this interface. 
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SIMATIC Safety - Fail-safe communication
 
The CP supports fail-safe communication via S7 connections. A fail-safe connection can 
run from the local CPU via the CP to the relevant communications partner, for example 
another F-CPU or a fail-safe distributed I/O system. 
You do not need to configure any special safety relevant properties for the CP. 
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–  Web server: Monitoring devices and process data (HTML process control) 
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FTP functions (File Transfer Protocol) for file management and access to data blocks 
in the CPU (client and server functions) 
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Sending e-mail via SMTP or ESMTP. The CP supports t SMTP-Auth for authentication 
on an email server and STARTTLS.