Apparatus is disclosed for apportioning charges on calls originating from coin telephones. At the end of the initial talking period which was paid for by the coin station, an overtime signal is sent to the called station. The called station signals if it will accept overtime charges and recognizing the...http://www.google.fr/patents/US4224472?utm_source=gb-gplus-shareBrevet US4224472 - Method and apparatus for apportioning call charges
Method and apparatus for apportioning call charges
