Incoming calls - Documentation

For your voice agent to answer your customers, your incoming calls need to be routed to it. There are two ways to do this: call forwarding, which is simple and requires no technical skills, or SIP integration, which is more robust and designed for businesses with a phone system.

Which method should you choose?

Standard call forwarding

Recommended to get started. You forward your current number to your agent’s number.5 minutes · No technical skills required

SIP integration

For phone systems (IP PBX, contact center). A direct connection between your infrastructure and Volubile.30 min to 1 h · Requires your telecom administrator

	Standard call forwarding	SIP integration
Setup	Codes on your phone or your carrier’s customer portal	Phone system configuration
Who does it?	You	Your telecom administrator or integrator
Carrier forwarding fees	Possible, depending on your plan	None
Context data (customer ID, store…)	No	Yes, via SIP headers

Not sure? Start with call forwarding to test your agent in real conditions. You can switch to SIP later without reconfiguring anything on the agent side.

Setup

Standard call forwarding
SIP integration

Volubile provides a dedicated number for your organization: once forwarding is on, your agent handles forwarded calls according to your configured scenarios. Enter this number, your line type, and your preferences: the codes to dial are generated automatically.

See all forwarding codes

Replace NUMBER with your agent’s number in international format (for example +33123456789).

Forwarding type	Mobile	Landline	Turn off
All calls	`*21NUMBER#`	`21NUMBER#`	`#21#`
Unanswered	`*61NUMBER#`	`61NUMBER#`	`#61#`
Unanswered after X seconds	`*61NUMBER**X#` (X = 5 to 30)	—	`#61#`
Line busy	`*67NUMBER#`	`67NUMBER#`	`#67#`
Off / no signal	`*62NUMBER#`	—	`#62#`
Cancel all forwarding	`##002#`	`#21#`, `#61#`, `#67#`	—

To check the status of a forwarding rule on mobile, dial *# followed by the service number, then # (for example *#21#).

My carrier doesn't accept the codes

Some plans (prepaid, restricted plans) and some internet boxes don’t support forwarding by codes. In that case, set up forwarding from your carrier’s customer portal or app, usually in a section such as My line > Call forwarding.

Your carrier may charge for forwarding, as an outgoing call to the agent’s number. Check your pricing before going live.Line outside France (Belgium, Switzerland, Germany…): if your agent’s number is French, forwarding is billed as an international call and isn’t always included in your plan. In that case, the SIP integration avoids these fees.

Test your forwarding

Call your usual number from another phone: a call placed from the forwarded line itself doesn’t trigger forwarding.

Your agent picks up and the call appears in the platform’s call history: you’re all set.

SIP integration (SIP Trunk) connects your phone infrastructure directly to Volubile. It’s the recommended method for professional environments: better quality, no forwarding fees, and the ability to pass context data to the agent.

Before you start, make sure that:

the SIP Trunk feature is enabled on your Volubile account (if not, contact your Volubile representative);
you have access to your phone system’s admin interface, or your telecom administrator is available;
you know your phone system’s public IP addresses, or you prefer credential-based authentication.

Open the SIP Trunk settings

In the Volubile platform, go to Settings > SIP > SIP Trunk.

Choose an authentication method

It ensures that only your phone system can send calls to your agents.

IP address authentication (recommended)

Enter the public IP addresses allowed to connect to the trunk.

A single address: 203.0.113.1
An address range (CIDR notation): 203.0.113.0/24

Recommended method: no secret to share or rotate.

Credential authentication

Create a username and password, then enter them in your phone system.

string

required

5 to 32 characters: letters, numbers, and hyphens only. Case-sensitive.

string

required

12 to 64 characters, with at least 1 number, 1 lowercase letter, and 1 uppercase letter. Case-sensitive.

Get your agent's connection details

Open the Telephony section of the agent you want to connect.

Write down these two values:

FQDN

Address of the Volubile server your phone system sends calls to. Example: volubile-efe2e38.sip-eu.vonage.com

string

Unique identifier used to authenticate your agent when connecting. Example: 5389079

Configure your phone system

In your phone system’s admin interface:

Create a SIP trunk to the Volubile SIP server address.
Set up the authentication you chose in step 2 (IP or credentials).
Route the relevant incoming calls to this trunk, using the agent FQDN identifier.

Send this page and the two values from step 3 to your telecom administrator: they’ll have everything they need to finish the setup.

Test

Place a call to a line routed to Volubile.

The agent picks up and the call appears in the call history with the correct caller number.

Is the caller number missing or wrong? Use the X-Volubile-System-From header (see below).

SIP headers (optional)

SIP headers let you correct some call information and pass context to your agent: customer ID, store, reason for calling…

string

Passes the caller’s number if it isn’t correctly transcribed in the platform. Send it when the call is set up, in international format.

string

Specifies the Volubile agent number if your phone system can’t override the called number (for example with a SIP redirect).

string

Data sent by your contact center, as per RFC 7433. Always stored in the user_to_user context variable.

string

Any custom data. Each header prefixed with X-Volubile is available to the agent as a context variable.

X-Volubile-System-From: +33612345678

X-Volubile-System-To: 2566458

X-Volubile-Store: 'My store'

Use this data in your agent

Use SIP context variables in your agent’s prompt.

Troubleshooting

Calls don't reach the agent

Call forwarding: check that forwarding is on (on mobile, dial *#21# for all-calls forwarding) and that the agent’s number is entered in international format. Test from a phone other than the forwarded line.SIP integration: check that the declared IP addresses match your phone system’s public IPs, or that the credentials are identical on both sides (they’re case-sensitive).

The caller number isn't displayed correctly

With forwarding, some carriers replace the caller’s number with yours. With the SIP integration, send the real number in the X-Volubile-System-From header.

I'm being charged for forwarding

This is normal with some carriers. Check whether your plan includes calls to the agent’s number, or switch to the SIP integration, which has no forwarding fees.

Need help? Contact your Volubile representative, who can help you with the setup.