Vocaltalk Pro app for iPhone and iPad

Vocaltalk Pro offers a simple user interface and superb audio quality for smooth Voice over IP experience.

Key features include:

- Bluetooth support.
- Lowest battery usage with highest reliability / stability on all iPhone models.
- Lowest audio latency of all iPhone models.
- Excellent audio quality, even on older devices.
- Supports calling over WIFI/EDGE/3G/LTE.
- SIP stack fully compliant to RFC.
- Background / multitasking support.
- Speakerphone mute and hold.
- Supports sending of DTMF.
- DNS SRV.
- Built-in echo cancellation.
- STUN support.