A method for processing an incoming call on a telephone line in a computer system, wherein a telephony circuit detects a pick-up by a parallel device coupled to the telephone line while maintaining high voltage isolation. The telephony circuit performs hard line seizures to cause the parallel device...http://www.google.de/patents/US5392334?utm_source=gb-gplus-sharePatent US5392334 - Off-hook detection and soft line seizure for telephone line sharing in a computer system
