Two telephone numbers, one for an outside call and one for an extension call, are registered for each of a plurality of one-touch buttons through a procedure the same as that used in placing a call conventionally and without providing new buttons. When an input designating an outside call is made before...http://www.google.fr/patents/US5054058?utm_source=gb-gplus-shareBrevet US5054058 - Telephone and telephone system having improved one-touch calling
Telephone and telephone system having improved one-touch calling
