Your question about Siemens S30810-Q2103-X IP

The function of the IP (Interface Processor) is to control the message exchange in the Hicom system between the switching unit and the servers.

2. Position in the System In the switching unit, the interface processor is connected via its multibus interface to the data processor multi processing (DP). Communication between the DP and the IP is carried out via a so-called dual port ram (DPR). The DPR can be addressed both by the DP via the multibus and via the local bus by the IP. Arbitration logic prevents simultaneous accessing from both sides. Data traffic to and from the servers is handled by an IEC bus controlled by the IP. In duplex operation, in order to ensure uninterrupted service, two common controls (control boards) are connected with a cross channel (CCH). The cross channel enables data exchange from one control board, i.e. from one redundant unit, to the other. One IP per control board is used as an interface to the CCH. The CCH is configured as an IEC bus. In its own control board, the IP is connected to the multibus. In the servers, the IP acts as switching gate to the IEC buses. Hence, for duplex systems the IP in the servers requires two IEC bus connections.
3. Bus Control Function The bus control accepts jobs via the operating system interface (command queues). The bus control sets up data connections, and clears them down after data transfer through the bus handler is complete. The bus control also time-supervises the jobs. In the case of errors, it informs the dependability system. Only the IP of the SWU (switching unit) has control over the bus, i.e. only the SWU's IP can determine which server IP will be the sender or receiver. The only initiative that may be taken by a server IP is the activation of the service-request line for the purpose of alerting the IP/SWU. If one server IP wants to connect with another server IP, it must inform the IP/SWU, which then establishes the connection. Only the bus control of the SWU/IP is master.
4. Bus Handler Function After connection set-up has been completed, the bus handler takes over the transfer of data via the IEC bus. After the end of data transfer, it informs the bus control.

The front panel of the board contains a 7-segment display, a RUN-LED, a reset key, a monitor key and a V.24 interface.