apparatives is something like "machined", but in this case "automated" is better.
The system observes all aspects of the transactions

I belive in the context they mean the type of system where the cashier does not use a handheld barcode device. In this sytem they move the consumer goods over a scanner flat bed device which reads the price and other data. Like most supermarkets nowadays with POS. This point of sales device decreases the labour of the cashier, especially in big markets where lots of customers would have stand in a long que. The computer aids in calculating the total sum and when the cashier enters the sum received by the customer the change to be returned if any is also calculated. The cashier only collects and returns money. Nowadays the use of credit or debit cards make things even simpler. No physical money transaction takes place. The customer receives the card receipt for the sale. I believe for verfahren one should say process but for apparative an interpretation like "computer assisted /aided" would be fit. In this case the observation means the scanner reading the data and hence watching over the whole process under the guidance of the computer is meant. So the computer monitors if the barcode has been read correctly or not and if so stores the data until the sale has concluded.