SIP is a protocol that gives you a unique identification (a SIP number or address) on the internet that you can use as a phone number or email address to make and receive voice calls for free.

SIP providers have thousands of local phone numbers in local area codes that can be assigned to their subscribers, and subscribers can allow their customers to phone them toll free from different ...

SIP trunking is a cost-effective option for modernizing legacy phone systems with minimal disruption. Discover the best SIP trunking providers and how to choose one in our complete buyer’s guide.