The serial adapter for use with a PPI connection is called a PPI Cable, RS232. The Siemens order number for this type of adapter is 6ES7 901-3CB30-0XA0.
Use this type of adapter to allow ClearSCADA to communicate with the Simatic S7-200 series of PLCs.
To enable the ClearSCADA Simatic S7 driver to communicate with a Simatic S7-200 series PLC, you need to set the PPI adapter to ‘Freeport’ mode. You do this by setting a DIP switch on the adapter.