# DUSphone — Encrypted calls via dus.net > Encrypted VoIP softphone for dus.net lines with HD quality and native call integration. (iPhone/iPad app by dus.net GmbH.) - Source: https://appshunter.io/ios/app/dusphone/id498522414 (this page in markdown: same URL + `.md`) - Developer: [dus.net GmbH](https://appshunter.io/developer/381540677) - Category: Business, Utilities - Price: Free - Rating: 3.00/5 from 3 App Store ratings · 4 written reviews indexed - Age rating: 4+ - Requires: iOS 17.0 · 11 MB - Languages: American English, Bulgarian, Croatian, Czech, Danish, Dutch, Estonian, Finnish, French (France), German (Germany) and 14 more - Released: 2012-02-09 - Data updated: 2026-07-24 - Monetization: free - User reviews in markdown: https://appshunter.io/ios/app/dusphone/id498522414/reviews.md ## What is DUSphone? dus.net GmbH proudly presents DUSphone – the VoIP softphone for your dus.net line. Make encrypted, HD-quality calls straight from your iPhone: to landlines, mobile numbers, and other dus.net lines. All you need is a dus.net plan – ready in minutes, including a starting balance of €0.45 for your first calls. See the plans at www.dus.net. Your benefits: • Encrypted calling over TLS and SRTP – your conversations stay private • HD voice quality powered by the Opus codec • Native call integration via Apple CallKit – calls appear on your lock screen and in your recents, just like regular calls • Always reachable: incoming calls ring reliably, even when your iPhone is locked or the app is closed (VoIP push) • Call landlines and mobile numbers – and receive calls on your dus.net number • Fast setup by scanning a QR code from the customer center – no password to type • Manage several lines at once (multi-account) • Company directory and device contacts – callers are matched by name • Keep an eye on your prepaid balance in euros at any time • Show or hide your caller ID per call (call anonymously) • In-call DTMF, hold, speaker, Bluetooth, and call history Privacy-friendly: no tracking, no ads. DUSphone is built on open-source software (baresip); the open-source licenses can be viewed in the app. Requirement: DUSphone needs a VoIP line at dus.net. More information at www.dus.net. ## Key features - Encrypted calling (TLS/SRTP) - HD voice quality (Opus codec) - Native call integration (Apple CallKit) - Reliable incoming calls (VoIP push) - Call landlines and mobile numbers - Multi-account management - Caller ID management ## Recent user reviews (4 of 4) All indexed reviews: https://appshunter.io/ios/app/dusphone/id498522414/reviews.md ### 3/5 — Medium great *2017-04-26* The app is a few years old, but so far it has done its job. Since it is built on old technology iOS now shows this disclaimer: These apps may slow down your iPhone and will not work with future version of iOS if they are not updated. If no update is available, contact the app developer for more information. I am hoping there will be an update soon, because I like having this app available when I want to use my dus.net account on my iOS device. ### 1/5 — Crashes immediately *2013-11-11* Doesn't work. Why is this in the App Store? ### 1/5 — So stupid! *2012-02-13* Once you get it, as soon as you open it, the thing keeps giving you reminders that say something like your account isn't credible anymore...I JUST GOT IT!!! Then when you go to call someone...EVERY NUMBER IS SUPPOSEDLY FAKE!!!! ### 1/5 — SUSphone *2012-02-12* Stinks :( ## Frequently asked questions about DUSphone ### What is DUSphone? DUSphone is a VoIP softphone application developed by dus.net GmbH that allows users to make encrypted, HD-quality calls from their iPhone using their dus.net VoIP line. It integrates with Apple CallKit for a native calling experience. ### How do I set up DUSphone? Setup is fast and easy. You can scan a QR code from your dus.net customer center, eliminating the need to type in passwords. DUSphone requires an active VoIP line with dus.net. ### Does DUSphone offer encrypted calls? Yes, DUSphone provides encrypted calling over TLS and SRTP, ensuring that your conversations remain private. This is a key feature for users concerned about call security. ### What is the call quality like with DUSphone? DUSphone offers HD voice quality, powered by the Opus codec. This ensures clear and high-fidelity audio for all your calls, whether to landlines, mobile numbers, or other dus.net lines. ### Can I manage multiple phone lines with DUSphone? Yes, DUSphone supports multi-account management, allowing you to manage several dus.net lines simultaneously. This is beneficial for users who handle multiple business or personal lines. ### How does DUSphone handle incoming calls when the app is closed? DUSphone ensures you are always reachable. Incoming calls will ring reliably even when your iPhone is locked or the app is closed, thanks to its VoIP push functionality. ### Is DUSphone free to use? DUSphone is free to download and use. However, it requires an active VoIP line with dus.net, and calls are made using a prepaid balance which includes a starting balance of €0.45 for your first calls. ### Does DUSphone have ads? No, DUSphone is privacy-friendly and does not contain any advertisements. It is built on open-source software and focuses on providing a clean user experience. ## Version history (last 5 releases) ### 7.1.2 — 2026-07-17 More reliable incoming call delivery: your device now also announces its push token directly during SIP registration. Plus minor technical improvements. ### 7.1 — 2026-06-24 New: Transfer calls – blind (direct) or with consultation (attended transfer). Also: • Call waiting & second call: hold one call, answer the other, switch easily • More reliable answering of incoming calls • Contact lookup when transferring • Bug fixes and refinements ### 7.0 — 2026-06-19 Welcome to the new generation of DUSphone! DUSphone has been rebuilt from the ground up and focused squarely on what matters most: reliable, secure calling over your dus.net line – modern, lightweight and built on an open-source foundation. • Encrypted HD calling via TLS and SRTP • Native call integration (CallKit): incoming calls ring just like regular phone calls – even when your iPhone is locked • Reliably reachable via VoIP-Push, even in the background • Set up in seconds with a QR-Code from the Kundencenter – no technical server details required • Multiple lines, an address book with caller ID, call history and balance display • Show or hide your number on a per-call basis • Now available in German, English, French and Spanish Enjoy your new DUSphone! ### 4.3 — 2013-07-29 + Added vanity buttons back to dialer layout. ### 4.2 — 2013-07-26 + Some bugfixes around crashing on some devices. If this bugfix did't fix your problem, please send the crash report to apple so we can debug the circumstances better. + UI redesign --- *Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-07-24.*