PulseSIP

A native iOS SIP phone client built with SwiftUI and PJSIP 2.14. Supports registering a SIP account, making and receiving calls, mute, hold, DTMF, and call history — with no CallKit dependency.

Features

• SIP account registration (any standard SIP server / Asterisk)
• Outgoing calls via a 12-key dialpad with real DTMF tone feedback
• Incoming call full-screen overlay with Answer / Decline
• In-call controls: mute, hold/resume, DTMF keypad (inband + RFC 2833 + SIP INFO)
• Call history with tap-to-callback and swipe-to-delete
• Network settings: STUN server, ICE, DNS SRV
• Auto-registers on launch if credentials are saved
• Credentials stored in UserDefaults; password stored in the iOS Keychain
• Call duration timer

Architecture

SwiftUI Views
      │
SIPPhoneManager          @MainActor ObservableObject — bridges PJSIP state into SwiftUI
      │
AKSIPUserAgent / AKSIPAccount / AKSIPCall    Objective-C wrappers around PJSUA
      │
libpjproject.xcframework    PJSIP 2.14 built from source (device arm64 + simulator arm64/x86_64)

Layer	Files
Views	Views/AccountSetupView.swift, Views/DialpadView.swift, Views/ActiveCallView.swift, Views/CallHistoryView.swift, Views/NetworkSettingsView.swift, ContentView.swift
Manager	Manager/SIPPhoneManager.swift, Manager/CallHistoryEntry.swift
Audio	DTMFPlayer.swift
ObjC SIP wrappers	SIP/AKSIPUserAgent.{h,m}, SIP/AKSIPAccount.{h,m}, SIP/AKSIPCall.{h,m}, SIP/AKSIPURI.{h,m}
PJSIP	PJSIP/libpjproject.xcframework, PJSIP/Headers/

Requirements

• Xcode 15 or later
• macOS 14+ (build host)
• iOS 15+ deployment target
• autoconf, automake, libtool (for building PJSIP from source)

Building

1. Install build tools

brew install autoconf automake libtool

2. Build the PJSIP xcframework

This step compiles PJSIP 2.14 from source and produces SIPPhone/PJSIP/libpjproject.xcframework. It takes roughly 15 minutes.

bash scripts/build_pjsip.sh

The script:

• Downloads pjproject 2.14.1 from GitHub
• Builds for iOS device (arm64) and simulator (arm64 + x86_64)
• Merges the libraries and packages them as an xcframework
• Copies all public headers to SIPPhone/PJSIP/Headers/

3. Open and build in Xcode

open SIPPhone.xcodeproj

Select an iOS Simulator or device target and press ⌘B to build, ⌘R to run.

Note: The xcframework is referenced in the project file but not committed to the repository. You must run build_pjsip.sh before the first build.

Project Structure

SIPPhone/
├── scripts/
│   └── build_pjsip.sh              # Automated PJSIP build script
├── SIPPhone/
│   ├── SIPPhoneApp.swift           # App entry point, injects SIPPhoneManager
│   ├── ContentView.swift           # Tab bar root + active/incoming call overlays
│   ├── DTMFPlayer.swift            # AVAudioEngine DTMF tone generator (pre-call)
│   ├── Info.plist
│   ├── SIPPhone-Bridging-Header.h
│   ├── Manager/
│   │   ├── SIPPhoneManager.swift   # Swift ObservableObject bridging PJSIP → SwiftUI
│   │   └── CallHistoryEntry.swift  # Codable call record model
│   ├── SIP/                        # Objective-C PJSIP wrappers
│   │   ├── AKSIPUserAgent.{h,m}
│   │   ├── AKSIPAccount.{h,m}
│   │   ├── AKSIPCall.{h,m}
│   │   ├── AKSIPURI.{h,m}
│   │   └── PJSIPCodecStubs.c       # Stub for disabled iLBC codec
│   ├── Views/
│   │   ├── AccountSetupView.swift  # SIP credential entry + register/unregister
│   │   ├── DialpadView.swift       # 12-key dialpad (pre-call) / DTMF pad (in-call)
│   │   ├── ActiveCallView.swift    # In-call screen with mute/hold/keypad/hang-up
│   │   ├── CallHistoryView.swift   # Recents list with tap-to-callback
│   │   └── NetworkSettingsView.swift # STUN, ICE, DNS SRV configuration
│   └── PJSIP/                      # Generated by build_pjsip.sh (not committed)
│       ├── libpjproject.xcframework
│       └── Headers/
└── SIPPhone.xcodeproj

Usage

1. Launch the app — if saved credentials exist, it registers automatically.
2. Go to the Account tab to enter or update SIP credentials and tap Register.
3. Switch to the Dialpad tab, type a SIP URI or number, and tap the green call button.
4. Incoming calls show a full-screen overlay with Answer and Decline.
5. During a call, use Mute, Hold, and Keypad buttons as needed.
6. The History tab shows recent calls; tap any entry to call back.
7. The Network tab configures STUN server, ICE traversal, and DNS SRV lookup.

DTMF

DTMF digits are transmitted three ways simultaneously to maximise server compatibility:

Method	When used
RFC 2833 (out-of-band RTP)	Servers with dtmfmode=rfc2833 (Asterisk default)
SIP INFO	Servers with dtmfmode=info
Inband audio tone	Servers with dtmfmode=inband; also provides local audible feedback

Pre-call dialpad keypresses play real dual-tone DTMF audio via AVAudioEngine (DTMFPlayer.swift).

Build Notes

PJSIP configuration

PJSIP is compiled with the following flags:

--disable-video
--disable-opencore-amr
--disable-ilbc-codec
--with-ssl=no

Audio uses iOS CoreAudio exclusively (PJMEDIA_AUDIO_DEV_HAS_COREAUDIO=1). A linker stub (PJSIPCodecStubs.c) satisfies a residual reference to pjmedia_codec_ilbc_init that pjsua-lib emits even when iLBC is disabled.

NAT traversal

Enable STUN in the Network tab (default: stun.l.google.com:19302). Without STUN, the device advertises its private IP in the SDP, and the remote server cannot route RTP back — resulting in one-way audio.

No CallKit

This app uses a custom SwiftUI call UI instead of CallKit. Incoming calls will not appear on the lock screen when the app is backgrounded.

SourceKit warnings

SourceKit shows "Cannot find X in scope" errors for ObjC SIP types and CallHistoryEntry because the PJSIP xcframework is not visible to the IDE's index. These are expected and clear on a full Xcode build (⌘B).

License

This project uses PJSIP, which is licensed under the GPL v2. The ObjC wrappers are derived from Telephone by Alexei Kuznetsov.