PortSIP Softphone is a SIP-based softphone application designed for iPhone. It utilizes Wi-Fi or 4G/LTE connections to enable users to make and receive calls and instant messages. When integrated with PortSIP PBX, PortSIP Softphone supports push notifications, allowing users to receive calls and messages even when the application is force terminated. With access to the iPhone's contact list, PortSIP Softphone offers a user-friendly interface for efficient communication management. It supports multiple calls, enabling users to switch between calls, merge and split calls, and perform attended and unattended transfers. Additionally, it supports video conferences with MCU (Multipoint Control Unit) support. PortSIP Softphone prioritizes security and incorporates advanced settings for secure call signaling and audio encryption. The application supports high-definition video calls up to 1080P with H.264 and VP8 codecs and ensures high-quality audio calls. The supported codecs include G.279, G.711a/u, Opus, AMR, AMR-WB, G.722.1, iLBC, GSM, and SPEEX-WB.