PSC Magellan 8500 Service Manual download pdf (Page 58)

METTLER TOLEDO

DIVA Service Manual 52

6.1.8 Dialog 06

With free programmable POS-Systems it is for a third party on principle possible, to manipulate

parts of the software, which are obligate to verification.

For this reason certifying agencies expects appropriate protection against such inadmissible

manipulations of third parties.

A protection against manipulations presents the Checkout-Dialogue 06 in conjunction with

precautions taken at the POS-Software.

6.1.8.1 POS-Software

The parts of the POS-Software, which are obligated to verify, have to be protected with

checksums (here called value CS), created by an appropriate method (for instance CRC16).

These checksums CS have also to be protected with checksums (here called value KW),

created by the CRC16-method in use with a polynomial P, which is known only by the

manufacturers of the scale and the POS-system. CS and KW both have a length of 16 bit.

Remark: KW represents the rest of the polynomial-division CS / P.

6.1.8.2 Checkout-Dialogue 06

The checkout-dialogue 06 presents for the scale the possibility, to request 1-5 pairs of

values CS/KW in cyclic intervals from the POS-system and check their validity. In case of

invalidity, no weight-results will be given from the scale to the POS-system, i.e. dealing with

the scale is not possible. With the request for the checksums, the scale sends a random

number, which has to be used from the POS-system for encoding the checksums. This

shall prevent a third party from monitoring valid checksums with simple measures. The

random number is an 8-bit-number, the higher nibble (here called Z1) is used for encoding

the CS-values, and the lower nibble (here called Z2) is used for encoding the KW-values.

The encoding of the CS-values has to be made by rotating them to the left for Z1 bits, the

encoding of the KW-values by rotating them to the right for Z2 bits.

For checking the conformity of the used protocol version in POS-system and scale, the

Checkout-Dialogue 06 presents for the POS-system the possibility to order the scale to

display the version number of the protocol. If the POS-system also displays the version

number, the conformity can be checked.

1 2 ... 53 54 55 56 57 58 59 60 61 62 63 ... 73 74

No comments

PSC Magellan 8500 Service Manual Page 58