The Siemens MPI Cable Profibus 6ES7972-0CB20-0XA0 is the programming cable that is interfacing with plc/hmi of the siemens brand. Mainly used it to program transfer to the new devices according to the ladder diagram, there is OCB20+ is the insolated and first transfer speed with data simulation in the software screen.
The PC Adapter USB A2 is the USB to MPI and PPI protocol adapter, support S7-300/400 PLC MPI/DP, or S7-200 PLC PPI communication. can Replace SIEMENS 6ES7972-0CB20-0XA0 / 6GK1571-0BA00-0AA0 with CD driver
PC adapter USB A2 USB adapter (USB V2.0) for connection of a PG/PC or notebook to SIMATIC S7 via PROFIBUS or MPI, SIMATIC S7 PC ADAPTER USB CONNECTION OF S7-200/300/ 400 PLC WITH USB-CABLE (5M) CAN BE USED UNDER WINXP/VISTA/ WINDOWS 7 32/64BIT. Use 6ES7 972-0CB20-0XA0 (PC ADAPTER USB) to download the s7-300 / 400 plc program