Guide: POS

What is a TSE? The technical security device explained

As of 13/10/2026 · This guide is not tax advice.

In short: The TSE (technische Sicherheitseinrichtung, technical security device) signs every transaction of an electronic cash register so that it cannot be changed unnoticed afterwards. In Germany it is mandatory for electronic cash registers (§ 146a AO) and must be certified by the BSI.

What the TSE is for

Since 1 January 2020, electronic recording systems with a cash register function must be protected by a certified technical security device. The legal basis is § 146a of the German Fiscal Code (AO) and the Cash Register Security Ordinance (KassenSichV). The aim is that takings are recorded completely and unaltered.

The TSE has three parts: a security module that gives every transaction a timestamp, a running transaction number and a signature; a storage medium; and a standard digital interface for exporting the data.

Hardware TSE or cloud TSE

A TSE can be a module plugged into the device, such as a USB stick or SD card, or a cloud TSE run by a provider. Both are allowed if the TSE is certified by the Federal Office for Information Security (BSI).

A cloud TSE needs no extra device, which makes it a good fit for registers on tablets, computers or phones.

Who needs a TSE

Every business that uses an electronic cash register, including a cloud POS on a tablet. There is no obligation in Germany to use an electronic register at all. A purely manual cash box needs no TSE, but takings must still be recorded completely.

What must be on the receipt

Under § 6 KassenSichV every receipt shows:

name and address of the business
date of issue and the start and end time of the transaction
quantity and type of goods or type and scope of the service
the transaction number
the price and the tax amount or tax rate
the serial number of the recording system or of the security module

The administrative guidance on the Fiscal Code (AEAO) also requires the signature counter and the check value. Many registers also print the TSE data as a QR code.

When the TSE fails

If the TSE fails you may keep selling. The outage must be documented, and the receipt must show that the TSE was unavailable. The fault must be fixed without delay.

Which fines apply

Using no TSE, or not using it correctly, is an administrative offence. The fine can be up to 25,000 euros (§ 379 (1) sentence 1 nos. 4 to 6 and (4) AO), even if no tax was evaded.

How MEVARIA helps

MEVARIA sets up a cloud TSE per location and signs every receipt. If the TSE fails you keep selling; MEVARIA marks the receipt and keeps an outage log. You create the TSE export and the DSFinV-K export yourself, for example for a cash audit.

Restaurant POS system for Germany, with TSE

Frequently asked questions

Does a POS on a tablet need a TSE?

Yes. Every electronic cash register needs a certified TSE, including a cloud POS on a tablet. A cloud TSE needs no extra device.

May I keep selling if the TSE fails?

Yes. The outage must be documented and visible on the receipt, and the fault must be fixed without delay.

Do I have to report the TSE to the tax office?

Yes. Since 2025 you report the register and TSE via Mein ELSTER, within one month of acquisition.

Does a manual cash box need a TSE?

No. Only electronic cash registers need a TSE. The duty to record takings completely still applies.