The highlights of the TFS-Dialog 400: - High-quality design with scratch-proof glass front made of 6 mm thick safety glass - Number of bell buttons freely programmable (1-4) - Programming via smartphone app TFS Set (Android < iOS) - Keyless door opening using a code lock -Function - Indirect ambient lighting and illuminated labeling field - The brightness can be adjusted separately - Operation on the analogue extension port of a telephone system