OS single station and OS client can be expanded by a signal module. These signal modules can control a horn and up to 3 different lamps or buzzer tones that represent a variety of message classes. Using a hardware timer (watchdog), the signal modules can detect and signal the failure of an operator station. A hardware acknowledgment button can also be connected.

The signal modules are installed in a PCI slot in the operator station.

They can be operated under the following operating systems:

• Windows 7 Ultimate 32/64-bit
• Windows Server 2008 R2 Standard 64-bit