An IP telephony system hotline dials a pre-programmed or predetermined telephone number virtually instantaneously when the phone goes off hook in order to summon help or a public safety agency. In addition to immediately dialing the police or fire, the system can be programmed to call several numbers...http://www.google.fr/patents/US6690675?utm_source=gb-gplus-shareBrevet US6690675 - User programmable fail-proof IP hotline/warm-line
