Siemens CP 1243-8 IRC Operating Instructions Manual page 12

Application and properties
1.2 Communications services
The telecontrol protocol "ST7"
For telecontrol communication, the CP uses the ST7 protocol on the application layer (OSI
layer 7) for communication via different telecontrol networks.
Functions and services of the telecontrol protocol
● Communication with the control center
An S7-1200 station with a CP 1243-8 IRC communicates via LAN/WAN with the master
station.
● SMS / E-mail
Event-driven, the CP can send SMS messages to mobile telephones and e-mails to PCs
with an Internet connection.
– SMS messages can be sent if the CP is connected to a mobile wireless network via
– If the CP is connected, e-mails can be sent via the Ethernet interface.
Both types of messages are configured in telecontrol communication in STEP 7 Basic.
The use of program blocks is not necessary here. For the configuration, refer to the
section Messages (Page 84).
● Inter-station communication
In dedicated line networks and with communication via the mobile wireless network and
the Internet (GSM/MSC), the CP supports inter-station communication between S7-1200
stations via the master station
With inter-station communication, the CP establishes a connection to the master station.
The master station forwards the messages to the destination station.
The partners for inter-station communication must already have been created in the
STEP 7 V5 project.
● Direct communication
In dial-up networks and Ethernet neworks, there is direct communication between the
subscribers.
Network types
The CP makes telecontrol communication possible via the following network types:
● Industrial Ethernet
● Dedicated line / wireless network
● Analog dial-up network, ISDN network
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the RS-232 interface.
Operating Instructions, 06/2015, C79000-G8976-C385-01
CP 1243-8 IRC