MPI to RS232

I think that the best idea is to buy a converter from a manufacturer. i.e. The MPI-protocol is quite complicated.
Just use the std siemens prog lead as that is exactly what it does! Or there is a Teleserve version for use with modems.


Thomas Hergenhahn

Let me know if you get better information. This converter is an intelligent device. The schematics would basicly show a microcontroller with RS232 interface on one side and RS485 interface on the other.

MPI is based on Profibus FDL. So the device must first be able to communicate on Profibus and integrate itself into the device detection/token passing mechanisms. Then it must accept requests from the RS232 side, store them until it is allowed to talk on the Profibus, get the answer and pass it back to the RS232 side.
I suppose MPI stands for the Siemens "Multi Point Interface" communication protocol. If you are talking about a different MPI disregard the following explanations.

First of all, I don't have schematics! But, MPI is a RS485 based communication and generally talking you need a 232<->3485 converter. If you need the whole MPI protocol, I suggest you to buy a converter (if you are a user; if you were assigned to design the converter ¡K).
A Siemens product is: 6ES7972-0CA23-0XA0
You can find details at:

Another product can be found at:

Some info about MPI:

If you do a search ( using MPI, rs232 you will find some useful links.


Hardware Guy

Its not the schematics that you need to know ultimately its the code that runs in the onboard CPU that you can't reproduce legally. The MPI adapter is far more than a simple RS-232 to RS-485 adapter.
The part # (read from the one in my desk drawer) is 6ES7 972-OCA23-OXAO

One port is marked MPI/DP & the other is RS232.