T 5.34 Deliberate re-programming of the destination keys on fax machines

In order not to have to enter frequently recurring recipients' fax numbers over and over again, some fax machines provide programmable destination keys. Frequently, recipients' fax numbers are not even checked when sending the fax. If an unauthorised person is able to change the way the destination keys are programmed and if he/she additionally makes sure that the fax transmissions received with the new destination address are forwarded immediately to the authorised recipient, he/she may conveniently read the fax correspondence of this recipient, possibly without ever being discovered.