Abstract: The present invention relates to a device for debiting of messages transmitted from a local network, A, to a public network, B. The user in the local network obtain or purchase stamps which can be used in connection with message transmission between the two networks. The stamps are purchased from subscriber equipments in the public network, B. The stamps are stored in a stamp register, where each stamp is given a unique number, date of issue, and to whom it has been issued, and time of validity. In connection with the use of the stamps the user state the stamp number which is identified by the system which in connection with the message transmission delete the mentioned stamp from the stamp register. The debiting for the stamps are made either at the purchase or in connection with the use of the stamps. Stamps which have been paid in advance and which have not been used within one in advance prescribed time of validity causes a repayment to the subscriber in the public network.