VoIP telephony usually results in considerable savings in telephone costs if the access interface (PSTN, ISDN2, ISDN30) does not have to be paid for. However, this may not be the norm. It is always necessary to accept offers from well-known language service providers, compare them and choose the best quality / price ratio.
In most cases it is also necessary to build a separate network infrastructure for VoIP telephony, possibly using management network elements to set the highest priority for telephony and to reserve the required bandwidth. In many cases it works. However, VoIP telephony can also be used in a shared data network with other computers.
The proposed VoIP solution therefore consists only in the selection of a suitable PBX version , but also in the selection of suitable and proven telephones , the network infrastructure and support in the selection of a provider of voice services.