Table of Contents

3CX

Status: ⚙️ configuration guidance — not yet formally verified. CalloraVoipSdk registers as a standard SIP extension and is expected to work with 3CX, but we have not yet run a validated interop test. Run your own acceptance test first.

Create an extension

In the 3CX console, add an extension and note:

  • the extension number (the SIP user, e.g. 1001)
  • its authentication ID and authentication password (under the extension's Options/Phone Provisioning — 3CX distinguishes the auth ID from the extension number)
  • the 3CX FQDN/IP as the registrar

Connect from the SDK

var connect = await client.ConnectAsync(new SipAccount
{
    Username  = "1001",                 // 3CX auth ID (may differ from the extension number)
    Password  = "auth-password",
    SipServer = "pbx.example.3cx.eu"    // your 3CX FQDN
});

3CX often uses a separate authentication ID distinct from the extension number. Use the auth ID as Username.

Expected configuration

  • Codecs — 3CX handles G.711 and Opus; keep PCMU/PCMA in PreferredAudioCodecs as a baseline.
  • DTMF — RFC 4733 telephone-events, which the SDK sends.
  • SRTP — 3CX supports SDES SRTP; pair its "SRTP enabled/required" setting with the matching SrtpPolicy.
  • NAT — for off-LAN registration follow 3CX's SBC/STUN guidance; the SDK's ICE is opt-in and experimental.

Validate

Registration, extension-to-extension dial, an external call via a 3CX trunk, DTMF, and SRTP if enabled. Reports welcome: info@bechstein.digital.

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