The onsite PBX is also known as an on-premise IP-PBX phone system. It is similar to a traditional PBX system in that it resides at a single location, such as in a computer equipment room or phone closet. The signalling is done with an IP phone to the IP-PBX server using a LAN. Calls can go through a traditional phone company or as VoIP using SIP trunking. Gateway cards can be used to connect the system to traditional lines.
Open source on-premise systems, such as Asterisk, are responsible for driving down costs for VoIP providers and manufacturers. This provides users with the ability to get the latest technology with many more features at a lower cost than what was traditionally available.
VoIP onsite phone systems are extremely feature rich since they have always been in active competition to traditional PBX solutions. The features available are typically greater in both quantity and complexity than those provided by traditional deployments.
The move to an IP-PBX business phone system using Snom telephones is beneficial regardless of the type of IP-PBX system chosen. When deployed with a Snom interoperability partner, however, it will ensure seamless feature support.