Due to our continuous expansion, our local telephone exchange was no longer adequate. It was expensive and inflexible. Moreover, we had a lot of ISDN lines and related high costs. Our IT company CDM ICT advised us to switch to VoIP. Since everything runs in the cloud, there is no longer a need for local hardware. So no more costs for maintenance and renewal. The redundant ISDN lines could also be removed immediately. We now have many more features (IVR, central phone book, etc) at a much lower cost.