Nowadays electronic cash registers support the responsible persons to manage increasing demands when selling goods or doing the bookkeeping. Starting in january 2017, there are new regulations regarding the treatment of electronic cash registers. One of them is the mandatory conformity against the german GoBD (Grundsätze zur ordnungsmäßigen Führung und Aufbewahrung von Büchern, Aufzeichnungen und Unterlagen in elektronischer Form sowie zum Datenzugriff) which defines rules to store and hand over electronic booking vouchers. Currently there is a transition period in germany, that ends in 2016, for cash register owners which do not fulfil these requirements. The new fiscal regulations, regarding the GoBD, leads to an urgent necessity for new electronic cash registers which meets those requirements. This paper examines some open-source solutions for point-of-sales (POS) software, regarding their compliance with the regulations of the german GoBD. A main topic involves the usage of these solutions in an environment of museums and public swimming pools, using an access control system. As a first step, the underlying scenario, covering an environment of museums and public swimming pools, using an access control system, will be described. Some general conditions will be covered as well as limitations. Based on this scenario, functional and non-functional requirements are worked out, which need to be addressed, in order to be compliant to the german GoBD. Afterwards some open-source solutions for the usage in POS environments will be examined. The observed solutions will be OpenBravo Java POS, uniCenta oPOS, POSper and Floreant POS. These solutions will be evaluated towards the functional and non-functional requirements. The result of this evaluation will be assessed with a prioritisation of the requirements. Based on this assessment, a recommendation will be made, whether or not the examined POS solutions are suitable for the designated purpose. This paper shows which requirements need to be addressed to use an electronic cash register, in order to be compliant to the german GoBD. Additionally, it will be evaluated which of the examined POS solutions can meet those requirements. Based on a clear establishment of the underlying scenario and the resulting requirements, manufacturer or user of electronic registers will get an overview of some open-source POS solutions and their functional spectrum.