A reinforcement device for a biological valve includes an arrangement of supports configured to establish a double-trigone geometry in the valve and coupled to a base upon which the valve may be mounted. A franking machine for use in such a postal system, in accordance with a method for tracking and tracing a piece of mail, has a printer for printing an identity code onto a label identifying one or more pieces of mail. With the presence of a corresponding control signal a line-switching connection is established from the first switch to the second switch and the data are then transferred through this connection. Each ring electrode has a connector terminal preferably formed thereon.