Pepeyee

Pepeyee is a VoIP softphone Android mobile phones based on the SIP protocol standards.
Pepeyee softphone is a software program for android devices allowing users make calls to other VoIP users or to landline and mobile networks usually for lower prices than the native GSM calls.
Features
VoIP calls with auto QoS using the SIP protocol standards (both incoming and outgoing calls)
Connects directly to your preferred VoIP server (no need for any intermediary media servers)
Android OS: all versions from 1.6
Connection: GPRS, EDGE, WiFi, 3G, 4G (all above 15 kbits)
Transport protocols: UDP, TCP, HTTP (HTTP available with tunneling only)
Built-in tunneling and encryption (for both the signaling and the media)
Codec: G.711 (PCMU and PCMA), GSM, Speex, iLBC, G.729 (G.729 is not available in the free version)
Automatic fine-tuning (including codec selection) depending on your peer capabilities, network speed and CPU power
AEC (acoustic echo canceller), Denoise filter, AGC (automatic gain control), PLC (packet loss concealment), Silence suppression
Detailed or simple configuration
System phone-book
Call history
Balance and rating display, call timer, status logs, detailed logs
Multi-tasking support -listening for incoming calls in the background
Speakerphone, Mute and Hold
IM (chat), SMS
DTMF (RFC2833 or INFO method)
NAT/Firewall support, stable SIP and RTP ports, auto QoS, light STUN protocol and auto configuration
Call park and pickup
Call transfer (attended and unattended)
Conference calls (built-in RTP mixer and transcoding when necessary)
DNS SRV record lookups
Logging support for trouble shooting
Supported methods: INVITE , ACK, PRACK, BYE, CANCEL, UPDATE, MESSAGE, INFO, OPTIONS, SUBSCRIBE, NOTIFY, REFER
RFC’s: 2543, 3261, 2976, 3892, 2778, 2779, 3428, 3265, 3515, 3311, 3911, 3581, 3842, 1889, 2327, 3550, 3960, 4028, 3824, 3966, 2663, 3022 and other drafts.