Control centres of telephony operators and other smaller companies that route telephone traffic have a system of regularly monitoring calls in real time. Dedicating a lot of attention to the quality of service, mostly monitoring and controlling quality of larger patterns of calls going to different destinations. The aim of the thesis was to implement improvements in the field of controlling quality of VoIP telephony, enabling visual representations of formal quality indicators of calls such as ASR, NER, ACD. Research was made of the existing tools on the market at the moment and summarized the requirements of the system. The thesis presents a solution of implementing ELK stack for editing data, making statistical analysis and visualization of quality indicators of calls. While evaluating this solution an upgrade is suggested for using Zabbix output of data filtered in Logstash to send them directly to Zabbix server. Findings are given resulting from pre-established system requirements.