--- title: "Connect Asterisk to WhatsApp with a QR Code — WhatsMCP Blog" description: "Step-by-step: link WhatsApp by QR code, then connect Asterisk PJSIP so WhatsApp calls ring your phones and your users dial WhatsApp numbers." url: "https://whatsmcp.com/blog/connect-asterisk-to-whatsapp-qr" --- Your phone system already handles calls for the office. Your customers call you on WhatsApp. This tutorial joins the two: you scan a QR code once, and from then on **WhatsApp calls ring your Asterisk phones**, and your Asterisk users can **dial WhatsApp numbers** as if they were ordinary phone numbers. There's no Meta approval and no new phone number: WhatsMCP links your existing WhatsApp number as a device — exactly like WhatsApp Web — and runs a small SIP "bridge" for it that registers into your Asterisk like a desk phone. Follow the steps in order. Each one ends with a quick check, so you always know where you stand. Plan on about 20–30 minutes. ![How Asterisk connects to WhatsApp through WhatsMCP: the WhatsApp number is linked by QR code, and the WhatsMCP bridge registers into Asterisk as a SIP extension carrying calls both ways](https://content.whatsmcp.com/uploads/asterisk_whatsapp_qr_architecture_cfae9afed4.webp) ## How it works (one minute of theory) - **Your WhatsApp number** is linked to WhatsMCP as a *linked device* by scanning a QR code. Your phone stays the main device. - **WhatsMCP runs a bridge for that number.** The bridge **registers to your Asterisk** with a username and password you create — to Asterisk it's just another SIP endpoint. - **Incoming WhatsApp call →** the bridge sends a SIP call to your Asterisk, to the extension you choose. - **Outgoing call →** Asterisk dials the bridge with the WhatsApp number as the destination, and the bridge places the WhatsApp call. So you don't configure a "trunk registration" to a provider. You create an **endpoint** for the bridge — and your Asterisk must be **reachable from the internet** so the bridge can register to it. ## What you need - **Asterisk 20, 22 or 23** with `chan_pjsip` (the default), and root access to edit its config. FreePBX works too — see the FreePBX notes near the end. - **A public address for Asterisk** — a static IP or a DNS name — with UDP 5060 (or TLS 5061) and your RTP port range open to the internet. - **A WhatsApp number** on a phone you can scan a QR code with. A Personal (or WhatsApp Business app) number — official WhatsApp Business API numbers can't take calls. - **A WhatsMCP plan with calls.** Of the Personal plans, **Pro** includes incoming and outgoing calls and SIP. See [Plans](/plans). - A SIP phone or softphone registered to your Asterisk for testing (we'll use extension `1001`). ## Step 1 — Create your WhatsMCP workspace 1. Go to [console.whatsmcp.com/register](https://console.whatsmcp.com/register?utm_source=blog&utm_medium=article&utm_campaign=connect-asterisk-to-whatsapp-qr&utm_content=step-1). 2. Enter your name and email, accept the terms, and press **Send confirmation link**. 3. Open the email, choose how you'll use WhatsApp (pick *Voice calls / SIP / PBX*), set a password and press **Create my workspace**. ✅ **Check:** you're signed in and the setup guide opens **Add a number**. ## Step 2 — Link your WhatsApp number with a QR code 1. On **Add a number**, choose **Personal WhatsApp → Link a device via QR**. 2. On your phone, open **WhatsApp → Settings → Linked devices → Link a device**. 3. Scan the QR code in the console. It refreshes every ~20 seconds — just scan the current one. 4. Wait while the progress goes **Code → Scanned → Syncing → Ready**. ![The WhatsMCP console Pair device page: a QR code above a progress indicator reading code, scanned, syncing, ready](https://content.whatsmcp.com/uploads/console_pair_device_fecfe5a9da.webp) ✅ **Check:** the console says *"Ready. +44 … is linked and synced."* — or *"Linked. … needs a plan before it runs."* if this isn't your first number. Either is fine; Step 3 sorts out the plan. > Keep the phone charged and online most of the time. WhatsApp unlinks devices whose phone has been offline for a long period. ## Step 3 — Put the number on a plan with calls 1. Open **Plans** for this number (from the console's plan page, or the *Choose a plan for this number* button after pairing). 2. Choose **Pro** — the Personal plan that includes incoming and outgoing calls and SIP — and complete checkout. ✅ **Check:** open the number's **SIP trunk** page in the console. It should show *"Voice plan: Pro. Incoming and outgoing calls…"* instead of *"This number needs a plan with calls."* Leave this page open — you'll come back to it in Step 8. ## Step 4 — Make Asterisk reachable The bridge connects to Asterisk from the internet, so Asterisk must know its public address and accept SIP and RTP from outside. **4a. Transport** — in `/etc/asterisk/pjsip.conf` (adjust the networks and address to yours): ```ini [transport-udp] type=transport protocol=udp bind=0.0.0.0:5060 ; Only if Asterisk is behind NAT (a router or cloud VPC): local_net=192.168.1.0/24 external_media_address=203.0.113.10 external_signaling_address=203.0.113.10 ``` **4b. RTP ports** — in `/etc/asterisk/rtp.conf`: ```ini [general] rtpstart=10000 rtpend=20000 ``` **4c. Firewall and router** - Allow **UDP 5060** and **UDP 10000–20000** to the Asterisk server (port-forward them if it's behind a router). - Turn off **SIP ALG** on the router — it rewrites SIP packets and breaks audio. - Use a long random password in Step 5: this endpoint is reachable from the internet. ✅ **Check:** from outside your network (a phone on mobile data with a SIP app, or an online port checker), UDP 5060 on your public address is reachable. > **Prefer encrypted signalling?** WhatsMCP also supports TLS (port 5061). Your Asterisk then needs a TLS transport with a certificate from a public CA for the name you'll enter in Step 8. Call audio is plain RTP either way. ## Step 5 — Create the WhatsApp endpoint in Asterisk Add this to `/etc/asterisk/pjsip.conf`. The bridge will log in with the username **`whatsapp`** — keep the endpoint name and the username the same, because Asterisk uses the caller's username to recognise the bridge's calls. ```ini ; ---- WhatsApp bridge (registers to us like a phone) ---- [whatsapp] type=auth auth_type=userpass username=whatsapp password=CHANGE-ME-to-a-long-random-password [whatsapp] type=aor max_contacts=1 remove_existing=yes qualify_frequency=60 [whatsapp] type=endpoint transport=transport-udp context=from-whatsapp disallow=all allow=g722,ulaw,alaw auth=whatsapp aors=whatsapp direct_media=no rtp_symmetric=yes force_rport=yes rewrite_contact=yes ``` Why these settings: - **`allow=g722,ulaw,alaw`** — the bridge offers exactly these: G.722 (wideband) first, then G.711 μ-law and A-law. Don't list `opus`; it isn't offered on the SIP side, and WhatsMCP converts WhatsApp's own audio for you. - **`direct_media=no`, `rtp_symmetric`, `force_rport`, `rewrite_contact`** — keep audio flowing through Asterisk and send it back to wherever the bridge's packets actually come from. This is what prevents one-way audio across NAT. - **`max_contacts=1`, `remove_existing=yes`** — one bridge per number; a re-registration replaces the old one. ✅ **Check:** nothing yet — we'll reload after the dialplan. ## Step 6 — Route incoming WhatsApp calls Incoming WhatsApp calls arrive in the `from-whatsapp` context, at the **extension to ring** you'll set in Step 8. Pick one of the two styles. **Option A — ring a fixed extension (simplest).** Leave the console's *Extension to ring* blank (it defaults to `101`) and route `101` to your phones: ```ini ; /etc/asterisk/extensions.conf [from-whatsapp] exten => 101,1,NoOp(Incoming WhatsApp call) same => n,Set(CALLERID(name)=WhatsApp) same => n,Dial(PJSIP/1001,30) ; or Queue(support), or Dial(PJSIP/1001&PJSIP/1002) same => n,Hangup() ``` **Option B — see who's calling.** Set *Extension to ring* to **`caller`**. The bridge then dials the **caller's WhatsApp number** as the extension, so you can show it and route on it: ```ini [from-whatsapp] exten => _X.,1,NoOp(WhatsApp call from +${EXTEN}) same => n,Set(CALLERID(num)=+${EXTEN}) same => n,Set(CALLERID(name)=WhatsApp) same => n,Dial(PJSIP/1001,30) same => n,Hangup() ``` Use Option B if you want the caller's number on your desk phones or in call logs — with a fixed extension, Asterisk only sees the bridge, not the caller. (There's also `9:caller`, which puts a prefix in front — e.g. `9447700900123` — if you'd rather match a prefixed pattern.) ## Step 7 — Let your phones dial WhatsApp Add a pattern to the context your phones use (often `from-internal`). Here users dial **9** followed by the full international number, and Asterisk sends it to the bridge: ```ini [from-internal] ; 9 + international number, e.g. 9447700900123 → WhatsApp +44 7700 900123 exten => _9X.,1,NoOp(Calling WhatsApp +${EXTEN:1}) same => n,Dial(PJSIP/${EXTEN:1}@whatsapp,60) same => n,Hangup() ``` The number you send must be **8–15 digits in international format, without a leading 0** — `447700900123`, not `07700 900123`. A leading `+` is tolerated. The WhatsApp call always goes out from the number you linked in Step 2. Now load everything: ```sh asterisk -rx "core reload" asterisk -rx "pjsip show endpoint whatsapp" ``` ✅ **Check:** `pjsip show endpoint whatsapp` lists the endpoint with its auth and aor. It shows *Unavailable* for now — the bridge hasn't registered yet. ## Step 8 — Point WhatsMCP at your Asterisk Back on the number's **SIP trunk** page in the console, fill in **Account settings**: ![The WhatsMCP console SIP trunk page for one number: registrar, transport, username, password, optional realm and extension to ring, with Test connection and Save buttons](https://content.whatsmcp.com/uploads/asterisk_whatsapp_console_sip_settings_7cd31d464f.webp) | Field | What to enter | |---|---| | **Registrar** | Your Asterisk's public address, e.g. `pbx.example.com` or `203.0.113.10`. Add `:port` only if it isn't 5060 (UDP) or 5061 (TLS). | | **Transport** | **UDP**, or **TLS (encrypted signalling)** if you set up Step 4's TLS option | | **Username** | `whatsapp` | | **Password** | The password from Step 5 (stored encrypted, never shown again) | | **Realm (optional)** | Leave blank — the bridge uses whatever realm Asterisk sends (`asterisk` by default) | | **Extension to ring** | Blank (= `101`, Option A) or `caller` (Option B) | 1. Press **Test connection**. WhatsMCP sends a real registration to your Asterisk. 2. When it says **"The registrar answered"**, press **Save**, then **Apply and restart** if prompted. ✅ **Check:** the page shows **Registered**. On the Asterisk side: ```sh asterisk -rx "pjsip show contacts" ``` You should see one contact under the `whatsapp` AOR with status **Avail**. ## Step 9 — Make your first calls **Incoming:** from another phone, call your WhatsApp number using WhatsApp. Extension `1001` rings; answer and talk. **Outgoing:** from extension `1001`, dial `9` and a WhatsApp number in international format — for example `9447700900123`. The person's WhatsApp rings, showing your linked number. ![Incoming and outgoing call flows between WhatsApp and Asterisk: an incoming WhatsApp call rings the chosen extension, and an outgoing call dialled as 9 plus the international number goes out over WhatsApp](https://content.whatsmcp.com/uploads/asterisk_whatsapp_call_flows_590e50ffc9.webp) ✅ **Check:** while a call is up, `asterisk -rx "core show channels"` shows a `PJSIP/whatsapp-…` channel, and you hear audio both ways. ## Troubleshooting | What you see | Likely cause | Fix | |---|---|---| | **Test connection** fails, nothing in Asterisk's log | The bridge can't reach Asterisk | Check the registrar address, port forwarding and firewall for UDP 5060 | | Test fails with an authentication error | Username or password differ | The username must be `whatsapp` and the endpoint name must match; retype the password | | Registered, but incoming calls don't ring | Dialplan doesn't match the extension | Check *Extension to ring* matches a pattern in `[from-whatsapp]` (`101`, or `_X.` for `caller`) | | Calls connect but there's no audio, or audio one way | NAT or blocked RTP | Set `local_net` / `external_*` (Step 4a), open the RTP range, disable SIP ALG; keep `rtp_symmetric`, `force_rport`, `rewrite_contact` | | Outgoing call fails immediately with **484** | Number format | Send 8–15 digits in international format, no leading 0 | | Outgoing call gets **486 Busy Here** | The number is already on a call | One call per WhatsApp number at a time | | **488 Not Acceptable Here** | No common codec | Make sure the endpoint allows `g722`, `ulaw` or `alaw` | | Outgoing calls refused with **403** | The plan allows incoming calls only | Choose a plan with outgoing calls | Useful Asterisk commands while testing: ```sh asterisk -rvvv pjsip set logger on # watch the SIP messages rtp set debug on # confirm audio flows both ways pjsip show contacts core show channels ``` ## Limits worth knowing - **One call at a time per WhatsApp number.** A second call gets *486 Busy Here*. Need more lines? Link more numbers. - **No keypad tones (DTMF) to or from WhatsApp.** An IVR that says "press 1" won't hear WhatsApp callers' key presses — use time-based routing, a queue, or speech instead. - **No hold or transfer requests across the bridge.** The bridge doesn't accept re-INVITEs or REFER, so plan call handling on the Asterisk side — test any transfer flow you rely on. - **Voice only** — no video on the SIP side. - **Audio is plain RTP**, even with TLS signalling. - **Personal numbers only.** Official WhatsApp Business API numbers can't take calls through WhatsMCP. - **Your phone stays the primary device.** If WhatsApp unlinks the device, re-scan the QR code (Step 2); the SIP settings stay. ## Using FreePBX instead The same idea in FreePBX's screens: 1. **Applications → Extensions → Add Extension → Add New PJSIP Extension**, e.g. extension `2000`, with a strong **Secret**. This is the bridge's account. 2. In **Settings → Asterisk SIP Settings**, set **External Address** and **Local Networks**, and check the RTP port range. 3. In the WhatsMCP console (Step 8), use **Username** `2000`, the extension's secret as **Password**, and your FreePBX's public address as **Registrar**. Set **Extension to ring** to the extension or ring group that should answer. 4. For outgoing calls, add **Connectivity → Trunks → Add Custom Trunk** with the dial string `PJSIP/$OUTNUM$@2000`, then an **Outbound Route** (for example prefix `9`) that uses it. 5. Set the extension's codecs to G.722, G.711 μ-law and A-law. ## No Asterisk? Use a hosted line If you don't run a PBX, the same **SIP trunk** page offers **Create a hosted line**: WhatsMCP hosts the registrar and gives you SIP credentials to use in any softphone or IP phone. See [WhatsApp SIP trunking](/sip) for the details. ## FAQ ### Does this need the WhatsApp Business API or Meta approval? No. The number is linked by QR code as a device, like WhatsApp Web. That also means it isn't an official Meta integration: WhatsMCP is independent, and linked-device use falls outside WhatsApp's terms — use a number you can spare and keep calls to people who expect them. ### Can I keep using WhatsApp on my phone? Yes. Your phone stays the main device and keeps working as normal; linking a device doesn't remove WhatsApp from it. ### Which codecs does the bridge use on the SIP side? G.722 first, then G.711 μ-law and A-law. WhatsMCP converts WhatsApp's own audio for you, so Asterisk needs no Opus module. ### Can my Asterisk register to WhatsMCP instead? Not for your own PBX — the bridge registers to *your* Asterisk. If you'd rather register to a server we host, use a hosted line. ### How many simultaneous calls can I make? One per linked WhatsApp number. Link more numbers for more simultaneous calls; each one gets its own SIP account. ## Get started [Create your WhatsMCP workspace](https://console.whatsmcp.com/register?utm_source=blog&utm_medium=article&utm_campaign=connect-asterisk-to-whatsapp-qr&utm_content=get-started), scan the QR code, and follow the nine steps above. For the architecture behind the bridge, read [Bridging WhatsApp and your PBX](/blog/bridging-whatsapp-and-pbx).