I would not say that the system has been hacked but on mobile phones the 'Ringing' noise or tone is generated by the mobile that is being called. This can usually be changed to music or a "a tape being rewound and then a breathing sound". This is likely to have been your mothers choice but if not I would recomend calling the network operator.
I think you just need to change your ringtone.
a camponologist
Someone is ringing you, you have your phone on vibrate.
I would say you are blocked. Quit calling.
Usually it's ringing because someone is trying to send a fax and the line is being dialed. Usually the flashing red is symbol that there is an error somewhere on the machine. If the ringing is beeping more than it is ringing, that can also be a symtom of an error message.
Ringing Voltage
ringing someone and threatening to rape/molest them
no. but you can still speak to them on skype, if someone that you have got is ringing them, and they add you to the conference.
a weezing noise like someone is breathing fast and hard
breathing into a bag should help regulate their breathing and calm them down
bell ringing
When someone is not breathing and does not have a pulse