The HITAC 5 was a true billing machine, developed as the successor of the HITAC-1. Although the majority of previous products used paper tape as their program memory media, the HITAC 5 used magnetic cards. This dramatically improved loading/storing of programs, and also improved ease-of-operation.
The HITAC 55 was developed as a product equipped with the features of a high-functionality billing machine, and the features of an online terminal for small computers (HITAC 8150). As a billing machine, it used the stored program system -- just like large computers -- and system usability was improved by providing dedicated keys for one-touch selection of programs for tasks such as billing and ledger processing. Terminal capabilities enabled distributed data input for creating clean data at the site where data was produced, in data processing areas where batch processing was the previous mainstream approach.