The control unit is a separate system that receives every transaction from the register, signs it with a secret key and returns a unique control number printed on the receipt. This makes it possible for Skatteverket to determine after the fact that no sale has been deleted.
What does the law say?
The Cash Register Act (SKVFS 2014:9) requires every register to be connected to a certified control unit. The unit must be approved by an accredited certification body and listed by Skatteverket.
Physical or cloud-based?
The classic control unit is a physical black box, like CleanCash, connected to the register over USB or the network. It works offline and needs no internet during the transaction.
A cloud control unit, like CleanCash Online, runs the same certified signing in a data centre. No hardware on site — perfect for food trucks, chains and registers that move. Requires a stable internet connection.
What to check with the supplier
- That the control unit is certified and listed by Skatteverket.
- That manufacturing numbers can be registered correctly.
- The level of support included in case of downtime.
- How the unit handles network outages (queue, retry, redundancy).
What happens if the control unit fails?
The register must not allow new transactions without valid signing. Good suppliers offer redundancy (secondary unit or cloud failover) and log the outage automatically. ViralConvert alerts and reports outages directly to operations.
How to choose the right type
Stationary restaurant with several registers: physical box per register or shared cloud unit. Mobile operation (food truck, catering, pop-up): cloud unit. Chain: cloud unit with central administration.
Reviewed by Product Manager Emil Lindgren, May 2026.