S 5.22 Compatibility check of the transmission and reception systems

Initiation responsibility: Head of IT Section, IT Security Management

Implementation responsibility: IT Procedures Officer

The reliability of data exchange depends on the compatibility of the sending and receiving systems involved. The necessary compatibility, in turn, depends on the complexity of the data to be exchanged. Before establishment of a regular exchange of data media, the following characteristics must therefore be examined in order to determine any incompatibilities and eliminate them if possible.

• Physical storage medium:

One prerequisite is that both the transmission and reception systems must have identical physical storage media. However, mechanical equivalence alone is not enough, as differences in parameters like tape speed or disk capacity can also lead to problems.

• Character set (e.g. ASCII or EBCDIC):

If the transmission and reception systems have identical character sets, physical reading allows the interpretation of individual sectors/blocks in the text which can be distributed sporadically on the data carrier. If the character sets are not identical, the transmitted data is interpreted incorrectly.

• Formatting the operating or file system of the data medium:

If both systems also have the same operating and file system, or the reception system is capable of reading the formats of other operating systems (some Unix operating systems can read DOS diskettes), then all files can be reproduced in the form in which they were present at the sender. This proves adequate for information not requiring any further formatting as carried out by most application programmes (e.g. word processors).

• Application software:

If application programmes were used for generating the data to be transferred, these programmes must be checked for their respective version, as the file formats might be different. The versions need not be identical in case of upward/downward compatibility.

• IT security software and IT security parameters:

If IT security products or the protective mechanisms of certain application programmes are used (cf. S 4.30 Utilisation of the security functions offered in application programmes), the compatibility of these products must be ensured. The sender and recipient must reach an agreement on the keys and passwords used.

In case of incompatibilities, additional measures or products must be provided to achieve the required conversion, or the transmission and reception systems must be identically configured.

Additional controls:

• Do the transmission and reception systems use the same IT products (hardware/ software)?

• Do the sender and recipient have compatible versions of application programmes?

• Does the recipient know the keys and passwords required for reading the information?