Siemens S5-135U/155U System Manual page 154

CPUs, Memory Cards, Memory Submodules, Interface Submodules
Communication
A PG-PLC link via SINEC H1 allows very advanced communication
via Backplane Bus
between the partners. For example, the user software can be loaded into the
with SINEC H1 CPU 948 up to eight-times faster than with serial communication.
For this link you will need, in addition to the CPU 948, a CPU 143 (Version
single-tasking software from Version 6.0 or multi-tasking from Version 2.0.
Note
You cannot implement communication via SINEC H1 in parallel with the
serial interfaces.
Communication via SINEC H1 is described in detail in the CPU 948
Programming Guide.
5-14
2.1) in the PLC and a PG7xx with SINEC H1 connection and the STEP 5
System Manual
C79000-G8576-C199-06