SIP trunking can replace existing ISDN lines to connect phone systems to the public phone network over the internet. This reduces costs through lower line rental and call charges compared to ISDN. It also provides improved business continuity through backup connectivity and flexibility to dynamically pool staff resources across sites. InTechnology is recommended for SIP trunking due to their managed MPLS network designed for voice, experience supporting both new and old telephony systems, and reliability from carrier-grade platforms.