The weatherproof enclosure, the integrated ISDN connection, the extremely low power consumption (approx. 2.5 W), power supply over several hundred meters via ISDN or Ethernet line, the integrated microphone and the speaker, the many sensors (motion detector, IrDa, temperature, remote interface), INTEL StrongArm CPU with 235 MIPS, serial interface, switched input, switched output (partly model-dependent). No moving parts make for an extremely robust, flexible system that has every right to call itself unique.