The Callcentric iPhone app allows existing Callcentric customers to place calls worldwide using their Callcentric account and save significant money over cellular carrier calling rates. This is particularly useful to customers who want to save money on international calls, or want the caller ID of their Callcentric account to show up on outbound calls they place instead of their iPhone phone number. Because of this, Verizon iPhone customers may have difficulty using the Callcentric app, especially if you are using it while not connected to Wi-Fi AND while in a 2G (1XRTT) data coverage area.

Callcentric alternatives

Acrobits Softphone

Acrobits Softphone, the perfect app for entry into the world of SIP. Featuring Video calls over Wi-FiCheck out the video tutorial and knowledgeable article at the links below.http://www.acrobits.cz/hesk/knowledgebase.php?article=62https://forum.acrobits.netWith loads of preconfigured providers and an extremely intuitive user interface, Acrobits Softphone is simple to configure and a delight to use. By using the app over 3G, you agree to abide by any restrictions your cellular carrier imposes and agree that Acrobits will not be held responsible for any fees or liability imposed by your carrier for using the app over 3G network.

Media5-fone SIP VoIP Softphone

IMPORTANT:Media5 Corporation announces the End-of-life (EOL) of the Media5-fone SoftClient on all platforms, including Media5-fone Free, Media5-fone Pro, and Media5-fone MPS, starting on August 31, 2018. Until then, support will be limited to fixing selected bugs and no new improvements or support on Operating System (OS) versions will be done. Please ask your mobile network operator before enabling the VoIP over 3G feature.

Linphone

Linphone is an open source app offering free audio/video calls and text messaging. With Linphone, you can be reachable at any time, even if the app is closed, with a WiFi or 3G/4G internet connection. Contact Belledonne Communications www.belledonne-communications.com for any specific development query.

Grandstream Wave

Grandstream Wave -Video IOS 7.0SIPGrandstream Wave6624BLFPBXUCM6100UCM6510 IP PBXGrandstream WAVEDNDLDAP , 720P. G.711/aG.722 (HD-audio)G.726-32GSMiLBCOpus Speex SIP IOS 7.0 SIPTLS128/256SRTP 6SIP66 6 24BLF UCMLDAP NATNATSTUNUPnP xml 3.5mm IOS DND, DTMFIn audio, RFC2833, SIP INFOFail-over 2G3GWi-Fi 4G