SAN FRANCISCO, CA--(Marketwired - Oct 24, 2014) - SIP (Session Initiation Protocol) is used by VoIP systems to manage VoIP phone calls. The phone calls operate differently from circuit-switched phone calls and are a much cheaper alternative. This is why many companies are switching to this option to save money. The specialists at 1010PhoneRates.com recently decided on the SIP trunk providers that are worth implementing into a business. The specialists looked into overall price, additional features, customer satisfaction reviews and more: