This device extracts the phone number of the calling party party from the ISDN signal. This signal is available on many routers out in the market. For each configured number a message may be read aloud using a text to speech module, an amplifier module and a set of speakers.
The message is configured of three parts: First a prefix from a configurable list of prefix messages. Then a message for the exact number actually calling and then a suffix from a configurable list of suffix messages.
"Hello " from the prefices.
"John " for the phone number (e. g. of John).
"is calling" from the suffices.
In total "Hello John is calling".
The current implementation allows for 16 prefix and suffix messages and 64 number specific messages. If the number is unknown the message "Unknown number" is read.