DTMF tones are used to trigger the DI/DO contacts of the Door Station by typing a pre-defined series of keys strokes on a telephone keypad whilst a call is established to the Door Station.
In order for the Door Station to support the DTMF function please ensure your Door Station is using firmware version 3.2.88 and above. If you need to update the firmware on your LILIN Door Station, the latest version can be download here.
Below is a screen-shot showing a correctly configured SIP menu on the LILIN Door Station. In the example below typing *1234# whilst a call is established to the Door Station will trigger the Digital Output.