Never miss a vital call, and save money. Make and receive calls from your Servcorp telephone number from anywhere in the world. No international call charges or cellular global roaming charges. # Requires a Servcorp subscription. Onefone also works seamlessly with your Cisco office phone, and includes the ability to swap between two calls, merge calls, and perform attended transfers. With multiple call support, you can quickly and easily handle incoming multiple calls, merge and split cal