Our application allows you to quickly turn on a realistic simulation of telephone beep signal. Which people usually hear in the tube while waiting for a response.
For the functioning of the application, you need two phones: on the one you are taking a call, on the other - the application runs. If you have one phone, waiting for a particular call, you can temporarily activate a forwarding: a wire number that you have on hand, or a friend's number. Thus, the application is installed (and runs) on your phone, you are taking (due to forwarding) the call to your number, but on the other tube.
Bugs, questions: firstname.lastname@example.org