T 5.32 Evaluation of residual information in fax machines

Depending on the technique a fax machine uses to store, process and print information, it might contain residual information of a varying extent after receiving a fax message. This information can be restored by persons having access to the fax machine or the relevant components.

In the case of fax machines using the thermal transfer technique, incoming fax messages are first written onto an intermediate foil which is then used to print the information. This foil is a consumable and must be replaced regularly; it is therefore designed to be easily removable. If an unauthorised person takes possession of this foil (by theft or removal) he will be able to reproduce the contents with a minimum of technical effort. Thus he would be able to view up to several hundred pages.

Most fax machines have an intermediate memory (document memory, buffer) in which outgoing faxes can be read until they are successfully transmitted and incoming faxes can be stored temporarily until they are printed. Depending on the fax machine, this memory can contain a large number of fax pages which can usually be printed by anyone who has access to the fax machine.