How to connect your number to a voice agent over SIP, without call forwarding

Plenty of numbers no longer run over a phone line but over the internet. That is VoIP telephony, the kind carriers such as Twilio, Telnyx or Netelip provide and the kind cloud PBXs use. A PBX is the system that takes your company’s calls and shares them out between departments.

Those calls travel over SIP, the language phones use to talk to each other over the internet. Think of it as a postal address. You tell your carrier which address to deliver your number’s calls to, and it delivers them there. Connecting your number over SIP means giving it Lera’s address, and from then on calls go straight to your voice agent.

Picture the customer service desk of an online shop, with a cloud PBX that shares calls between shipping and billing. It connects its number to Lera, the agent answers first, handles the everyday questions and passes billing anything that needs a person.

If your number is with a traditional landline or mobile carrier, the usual route is to forward it to a Lera inbound line, as we explain in our guide to forwarding calls to a voice agent, at leracore.com/en/resources/forward-calls-to-a-voice-agent.

If it already runs over the internet, connect it directly. Callers dial your usual number, there is no second call and no forwarding cost, and your agent calls and transfers from your own number rather than a Lera line.

An Administrator on your account does this. In Phone numbers, click Connect my phone and choose Connect your VoIP number or From your PBX (SIP). Both ask for the same things.

The panel shows you Lera’s address. Copy it exactly as it is into your carrier or your PBX, wherever you set where incoming calls go. In Twilio, under Elastic SIP Trunking, you create a trunk, paste the address in the Origination tab and add your number in the Numbers tab. The step-by-step guide sits just below the address.

Type your number with the country code in front, +34 for Spain, and a name to recognise it if you like, such as Customer service. Click Connect.

Then open the number in the list, pick under Answering agent which of your agents answers and click Save. The agent has to be published.

On the number’s page, click Check the connection and then I’ve turned it on, check. Call your number from another phone, such as your mobile, and when your agent answers the panel tells you the call got in. The test call is charged like any other and lasts a few seconds.

If nothing arrives within a minute and a half, check that your number already points to Lera’s address and that you typed it the way you dial it, with the country code. If the page warns that calls are not getting in, click Reconnect, and if nothing changes, write to us.

By default, Lera accepts any call addressed to your number. Once you see calls getting in, you can make sure only your carrier or your PBX can send calls in, on the number’s page, under Who can deliver calls to you, with the Protect the entry button. It is optional.

If your carrier or your PBX supports it, it identifies itself with a username and password on every call, which Twilio and Telnyx do not support. Set the same thing up on your carrier’s side and, after saving, call again to check that calls still get in. Lera does not store the password.

For your agent to call from your number, connect the outbound side too, which is a separate route from receiving at your carrier.

Open the number and, on the Outbound calls card, click Activate outbound. Paste your carrier’s Provider SIP address, SIP username and SIP password and click Activate outbound again. In Twilio these are the Termination URI and a Credential List on the same trunk that already receives your calls, because a number can only sit in one. Lera uses the credentials to create the connection and does not store them.

On the same card, pick the agent that calls and click Save. The people you call see your number. Your software requests the calls through the API, and you can try one from the agent’s page, under Test, Outbound test. We cover it in our guide to automated outbound calls, at leracore.com/en/resources/automated-outbound-calls-with-a-voice-agent.

With the outbound side connected, the agent dials from your number and joins both sides. That lets it Brief the person, which means telling them who is calling and what they want before connecting them. It can also dial an extension, the short number that only exists inside your PBX, such as 205 for billing, as long as your PBX allows extensions to be dialled from outside. The person receiving the call sees your business number.

Without it, the agent asks your carrier to pass the call on itself, which is called SIP REFER, and then it cannot brief the person or dial an extension. Many carriers ship with it switched off. In Twilio you turn it on in the trunk’s General tab, with Call Transfer (SIP REFER), Enable PSTN Transfer and Set caller ID as Transferor under Caller ID for Transfer Target.

Pass the call to a number that does not lead back to Lera, such as an extension’s own number, a group’s number or a mobile, because if you pass it to the connected number it comes back to your agent. If you would rather your PBX take the call and route it itself, that is set up between your IT person and the Lera team. There is more detail in our guide to passing a call to your team, at leracore.com/en/resources/pass-the-call-to-your-team.

If you are a telephony integrator or you sell PBXs or software to other businesses, you can work with Lera as a partner, an account the Lera team approves after talking to you. Each client has its own space, with its agents and its numbers, and you manage its telephony.

To connect a client’s number, open their sheet under Settings, Clients, click Go to client and follow the same steps. From your own software, the API offers import_phone_number, with the X-Lera-Client header, and check_phone_number to see whether the number is connected and its agent published. The outbound side is connected from the panel, and your client’s people see their numbers without being able to change them.

There is no surcharge on your own number. Calls you receive and calls your agent makes count as your agent’s minutes, and passing a call to a person costs nothing extra. Your carrier bills you for the call’s time on its network, as it does today.

Connecting your number does not use up your inbound line. Your account’s first one stays included in case you want to forward another number one day.

If you take a plan, connecting your number and passing calls come with every plan. Outbound calls start at Professional, and requesting them through the API at Advanced. On pay as you go, like partners, and while you are trying Lera, you get everything.

Will callers notice anything? No. They dial your usual number and the call goes straight to your agent.

What if my carrier does not support SIP? Forward your number to a Lera inbound line. Your customers keep dialling the same number and your agent answers.

Who can connect a number? An Administrator on the account. If your account is a partner’s client, the partner does it.

How much does it cost to try? €20 free credit, no card needed. Connect your number, call it from your mobile and hear your agent answer before you decide anything.