Your question about Siemens S30810-Q2093-X LCU

For direct connections, in which case the LCU (Line Control Unit) acts as a DCE, the connection can be made with a 1:1 cable.

If a modem is used, the connection between the modem and the LCU must be made with a cable in which the corresponding wires are crossed, since the modem can only adopt the DCE function; the LCU must hence be operated as a data terminal.

For further information a connecting the LCU, on the V.24-interface and on connecting a service terminal or a modem, see the LBU board description!

The front panel of the board contains three LEDs (RUN, H2, H3) and two V.24-interface. Two V.24 interfaces are used for connecting terminals and/or data processing systems to the Hicom system.