Halcyon vs Sip:phone

Halcyon is a free, pre-1.0 Android softphone built on PJSIP and integrated with Android Telecom. It registers with a PBX over UDP, TCP, or TLS, advertises RFC 8599 push parameters, and supports several SIP identities with an account selected for each call. When server-side push is configured, the registrar sends a data-only FCM message before an incoming INVITE to wake the device. Without push, Halcyon uses a foreground SIP service with permanent TLS registration and the associated battery cost. Its Android ConnectionService handles tel: and sip: calls, including from the lock screen, while Telecom-native routing supports Bluetooth headsets and Android Auto. Listed audio codecs are Opus, G.722, AMR-WB, and G.729; video codecs include VP8, VP9, and arm64 MediaCodec H.264. Media uses SRTP encryption, with ZRTP on the roadmap. Android 8.0 or newer is required; signed APKs are available from GitHub Releases.

Sip:phone extends Sipwise Class 5 Softswitch and CPBX services to Android and iOS as a mobile extension of an existing business phone system. It is intended as a white-label client for operators using Sipwise NGCP, who can customize its appearance and publish it under their own name in the Apple and Google app stores. Subscribers are managed on Sipwise C5 through interfaces such as its web interface or REST API; users can sign in with a username and password or scan a server-generated QR code. Calling includes audio and video, hold, two simultaneous calls, three-way conferences and blind or attended transfers. The app synchronizes phone contacts with Sipwise C5 subscribers and can show presence for favorite contacts. Administrators can configure whether a desk phone or mobile app rings first, or have either ring alone. Sip:phone requires an existing Sipwise server account and is not intended to support emergency calls. The App Store download is free, but commercial use requires a Sip:Phone App license; pricing is available from Sipwise Sales.