One device, one number strategy
The office extension travels with the employee. Calls to the company number ring the mobile over data; outbound business calls present the company identity — lower mobile charges, consistent customer-facing numbers.
THE MOBILE ENDPOINT
PentaPhone
Company VoIP and mobile GSM, unified in one secure Android dialer.
PentaPhone turns every Android phone into a fully-fledged extension of the company phone system — the desk-phone feature set, standards-based push reachability, and encryption on every call, on the phones your employees already carry.
→ SIP + GSM→ DTLS-SRTP→ RFC 8599 push
Executive summary
One dialer for the whole company
PentaPhone becomes the phone's default dialer, so company VoIP calls (SIP) and regular mobile (GSM) calls live in the same interface, the same call log, and the same contacts. Employees keep one device and one habit; the company gains desk-phone features, central control, and full call security on every handset.
PentaPhone is the mobile endpoint of the Pentacomm communications platform, built and supported by Pentagon Business COM. Because it speaks open telecom standards end to end, it also interoperates with any standards-compliant SIP infrastructure — no proprietary lock-in at the protocol layer.
A look inside
The app, screen by screen
Real captures from the app — choosing the line, the active call, hold and swap, live quality and QR provisioning.
Pick the line per call — SIM 1, eSIM or the company extension, from the same keypad.
The call goes out over the company extension, in the phone's native call screen.
Mute, earpiece, DTMF pad, hold, add call and transfer — on every call.
Two calls at once: one active, one on hold, swap with a tap.
The call's MOS score, live on screen — quality is visible without a separate test.
The account is added by scanning a QR code from the administrator; registration state stays visible.
Why it matters
What decision-makers get
Reliable like a phone, not like an app
Standards-based push wake-up (RFC 8599) rings the phone even when the app is closed or the device is in deep sleep, with an automatic fallback where push is unavailable. Reachability is never silently lost.
Secure by default, not by option
Signalling runs exclusively over TLS and voice media over DTLS-SRTP; encryption cannot be switched off. Credentials live in hardware-backed encrypted storage, and private on-premises certificate authorities are supported.
Truly native Android integration
As a Telecom-framework default dialer, PentaPhone calls behave like ordinary phone calls: Bluetooth car kits, headsets, and wearables just work, and emergency numbers (112/911) always use the mobile network.
The desk-phone feature set, on mobile
Call waiting, swap, blind and attended transfer, voicemail with message-waiting indication, and a unified company call log.
Deployable and supportable at scale
Multi-account and dual-SIM aware, QR-code provisioning, automatic registration after reboot, live call-quality metrics, and one-tap redacted diagnostics for fast IT support.
Capabilities
Everything a business softphone needs
Each area below is shipped and production-ready today, in one application, with a guided first-run onboarding.
Unified calling
- Outbound & inbound VoIP (SIP) over Wi-Fi or mobile data
- Native GSM calling, dual-SIM aware, in the same dialer
- Per-call line selection (SIP account / SIM 1 / SIM 2) with saved defaults
- Full-screen incoming-call UI, including over the lock screen
- Emergency numbers always forced onto the mobile network
In-call experience
- Mute, hold/resume (both directions), in-call DTMF keypad
- Audio routing: earpiece, speaker, wired headset, Bluetooth
- HD voice with hardware echo cancellation & noise suppression
- Calls survive network changes via automatic media re-negotiation
- Proximity handling, call timer, live quality indicator
Business call control
- Call waiting — second incoming call with automatic hold
- Swap between two calls; add a second outbound call
- Blind transfer and attended (consultative) transfer
- Voicemail: message-waiting indication, one-tap dial, unread badges
Contacts & call history
- Device address book integration — search, favorites, speed dial
- Caller-name resolution on incoming calls and in the call log
- Unified SIP + GSM call log, grouped by number, filterable per line
- Missed-call notifications with unread badges
Administration & deployment
- Multiple SIP accounts registered in parallel
- QR-code and setup-link provisioning; guided onboarding
- Automatic re-registration after reboot and app updates
- Encrypted credential storage; certificate review & revocation
- One-tap redacted diagnostic export for IT support
Quality & observability
- Live in-call quality metrics: MOS score, jitter, packet loss
- Per-call quality summary for troubleshooting
- Privacy-scrubbed crash reporting, fully symbolicated
- Always-on bounded local logging — zero start-up cost
What sets PentaPhone apart
Engineered for reliability, security, and trust
Registrar-integrated push wake-up
Incoming calls wake the phone through a high-priority push triggered by the SIP registrar itself (RFC 8599) — no third-party SIP push gateway sits in the call path. The phone rings from a closed app, deep sleep, or battery-optimized state, and falls back automatically to a battery-aware persistent connection on devices without push services.
No unencrypted mode exists
Signalling is SIP over secure WebSockets (TLS) only, and media encryption (DTLS-SRTP) is compiled in as mandatory. The product cannot be misconfigured into sending calls in the clear.
Private PKI, first-class
Ships with the Pentacomm root CA scoped to the app (it never touches the device trust store) and supports on-premises or self-signed server certificates through an explicit administrator approval flow with review and revocation.
A dialer, not an app pretending to be one
Deep Android Telecom integration means system-grade behaviour: lock-screen answering, Bluetooth and car-kit controls, correct audio focus, and emergency-call safety (112/911 always over the mobile network).
Controlled supply chain
The SIP protocol stack is developed in-house and the WebRTC media engine is built from audited source. No third-party SIP libraries sit in the call path, and quality, security, and support remain under one roof.
Privacy-respecting telemetry
Crash reports are scrubbed of personal data before leaving the device; diagnostic bundles are redacted and shared only by explicit user action. No advertising or analytics SDKs.
Continuously verified
The signalling stack is covered by an automated protocol test suite (golden traces from real platform traffic), and every release passes CI build, test, and lint gates before it ships.
The bottom line
One dialer. Every call encrypted. Reachable around the clock — on the phones your team already carries.
For the IT team
Built for the team that supports it
The controls an administrator needs live in the app, not buried in Android's settings.
- Default outgoing line
- The line used when Contacts, the voice assistant or other apps call a number.
- Trusted certificates
- The certificate authority the app trusts for secure connections is stated explicitly.
- Battery optimization
- The exemption is surfaced in the app, so the phone stays reachable for calls in the background.
- Export diagnostics
- A one-tap troubleshooting bundle for support — logs and account status, never passwords.
Transport architecture
Why WebSocket-only signalling
Most softphones still speak SIP over UDP — a transport designed for desk phones on a managed office LAN, not for devices that roam across corporate Wi-Fi, guest networks, hotels, and mobile data. PentaPhone deliberately ships a single signalling transport — SIP over secure WebSocket (RFC 7118) — and the difference shows up exactly where softphones traditionally fail:
Traditional SIP softphone (UDP / TCP / TLS)
PentaPhone (SIP over WSS)
Restrictive networks
UDP port 5060 is routinely blocked or throttled on corporate firewalls, hotel and guest Wi-Fi — calls simply fail.
Signalling is indistinguishable from ordinary HTTPS and traverses any network where the web works — no firewall tickets.
Router "SIP ALG"
Consumer and SMB routers rewrite SIP packets in flight — the classic cause of one-way audio and dropped registrations.
TLS-encrypted WebSocket frames are opaque to middleboxes; there is nothing to inspect or mangle.
NAT traversal & inbound calls
Incoming calls depend on fragile keepalive timers holding a router port binding open.
One client-initiated connection; the server delivers every request — INVITE, BYE, CANCEL — back over it by construction (RFC 7118, RFC 5626).
Large SIP messages
WebRTC-sized SDP bodies exceed the UDP packet limit, fragment, and get silently dropped.
Stream transport — message size is a non-issue.
Encryption
Optional and often left off; plaintext-UDP deployments remain common in the field.
Always on — TLS is the only transport that exists in the product.
Device attack surface
A listening SIP port is exposed to internet scanners — "ghost calls" and registration probes.
No listening ports; the app only ever dials out.
The payoff
Calls connect on networks where traditional softphones fail — with no firewall tickets, no SIP-ALG battles, and no exposed ports.
Technical profile
Technical specifications
- Platform
- Android 10 and newer (API level 29+), phones and tablets with telephony.
- Application type
- Native Android application (Kotlin); registered system default dialer via the Android Telecom framework.
- Signalling
- SIP over secure WebSocket (WSS) — TLS-encrypted, firewall- and NAT-friendly (standard HTTPS port model).
- Media engine
- WebRTC, built from source and shipped with the app; per-call peer connections; concurrent-call capable.
- Audio codecs
- Opus (preferred, wideband) · G.722 (HD) · G.711 A-law / µ-law — negotiated per call.
- Audio processing
- 48 kHz pipeline with hardware acoustic echo cancellation and noise suppression.
- Media security
- DTLS-SRTP key exchange + SRTP encryption, enforced — no unencrypted media path exists.
- Authentication
- SIP digest, MD5 and SHA-256; credentials in hardware-backed encrypted storage.
- Certificates
- Public CAs, bundled Pentacomm root CA (app-scoped), and administrator-approved private / self-signed CAs.
- Incoming-call wake-up
- High-priority push per RFC 8599, triggered by the SIP registrar; automatic fallback to a persistent connection where push is unavailable.
- Accounts
- Multiple SIP accounts in parallel + dual-SIM GSM; per-line outbound routing with saved defaults.
- Provisioning
- QR-code scan and setup-link zero-touch flows; manual configuration; guided onboarding.
- Emergency calling
- Emergency numbers always routed over the mobile network, never over VoIP.
- Backend compatibility
- Pentacomm platform; any RFC-compliant SIP server with WebSocket transport and WebRTC-compatible media (DTLS-SRTP).
- Diagnostics
- Live MOS / jitter / packet-loss metrics; per-call quality summaries; one-tap redacted diagnostic export; privacy-scrubbed crash reporting.
- Releases
- Semantic-versioned, CI-gated builds; distributed via Google Play, with a managed internal channel for pilots.
- Licensing
- Proprietary commercial software by Pentagon Business COM.
Product roadmap
Where PentaPhone is heading
The app evolves alongside the Pentacomm platform. The following capabilities are planned on the same standards-based foundation.
Conference calling
Three-way and multi-party audio conferencing from the in-call screen, built on the Pentacomm audio conference bridge.
Video calls
1:1 video calling — the shipped media engine already carries the full WebRTC video stack, secured by the same DTLS-SRTP edge.
Visual voicemail
Per-message voicemail list with in-app playback — and transcription, paired with the platform's voicemail-transcription module.
Company directory
A synchronized directory of colleagues and shared contacts served by the platform, merged into the Contacts tab with caller-name lookup.
Who it is for
Built for teams that live on the phone
Multi-site enterprises & hybrid teams
one extension per employee that works identically at the desk, at home, and on the road, with consistent policy and one call log.
Mobile-first workforces
field service, sales, and operations teams that need the company number with them, without carrying a second device.
Organizations replacing desk phones
keep the PBX feature set (transfer, hold, voicemail, call waiting) while retiring per-desk hardware.
Regulated and security-conscious organizations
every call encrypted end to end, credentials in hardware-backed storage, and support for a fully private PKI.
Put your phone system in every pocket.
See Pentacomm running on a live appliance and PentaPhone registered against it — or against your existing SIP platform. Talk to us about a proof-of-concept, licensing, and deployment.
Talk to us