Transfer calls with context using SIP Refer from Twilio and SIP UUI Header

Transfer calls with context using SIP Refer from Twilio and SIP UUI Header

Today we are thrilled to announce that SIP Refer from Twilio is now generally available for call centers looking to transfer calls from Twilio to their SIP infrastructure. This enables call centers to save money on their calls by removing Twilio from the call path. When used in conjunction with SIP UUI Headers, a feature released this summer, context from Twilio can be passed along with the SIP Refer.

Call Centers can use SIP Refer and SIP UUI Headers to transfer calls from Twilio to their internal SIP infrastructure, while maintaining call context, in order to transfer the call back to their IP infrastructure and handle sensitive information internally.

Transfer the call back to your IP infrastructure

When a customer calls into a contact center through Twilio to speak with Agent 1, Agent 1 can now transfer the call and pass relevant information to Agent 2 through their internal SIP infrastructure and discontinue the Twilio call leg.

Call centers can use SIP Refer from Twilio to transfer calls from Twilio to their internal communication infrastructure.

For example, a customer could be driving on the road when their car breaks down. They call their car insurance company’s toll-free number and talk to an agent about their problem. The agent gathers all the information about the customer and is ready to call their associated tow company so the customer and car can be picked up. Twilio now transfers (using SIP REFER) the call along with contextual information (using UUI header) of the caller, removing Twilio from the call path. With SIP UUI Header, the agent is able to pass on the context of their conversation with the customer, including their location, to the tow company so the customer doesn’t have to repeat themselves.

Handle sensitive information internally

For regulated industries, this enables them to remove Twilio from the call path and handle sensitive information within their internal SIP infrastructure.

SIP Refer also enables call centers in highly regulated industries to keep sensitive information internal. For example, a business may want customers to contact them using a Twilio toll-free number. When the customer calls, it is bridged to Twilio through SIP Interface to an IVR. When the customer needs to talk to an agent or leave a voicemail which has sensitive information, Twilio (using SIP Refer) can now transfer the call from the IVR to the agent removing itself from the call. This ensures the sensitive information of the customers is protected. With SIP UUI Header, the information the customer shared in the IVR is passed along to the agent so no context is lost.

How SIP Refer from Twilio works

Today, Twilio supports SIP Refer from Twilio to IP infrastructure. The <Refer> verb can be invoked on both inbound and outbound SIP calls. For example, on an inbound SIP call to a Twilio SIP Domain, you may want to transfer the caller to back to your in-house or legacy SIP infrastructure. By initiating the <Refer> verb, Twilio instructs your SIP device to initiate a new call to the external system and replace the Twilio leg with that new call.

You can initiate a <Refer> at any point in the duration of a call. For example, with an outbound SIP call created by the <Sip> noun or the Twilio REST API to a SIP Domain, can be used at any point to transfer the caller back to your in-house or legacy SIP infrastructure. By initiating the <Refer> verb, Twilio instructs your SIP device to initiate a new call to the external system and replace the Twilio leg with that new call. 

When using <Refer> to transfer a caller between independent internal systems, there may be a desire to pass contextual information about the call. For example, if you are building an IVR on Twilio that collects a customer's account number and reason for calling before transferring the call to a call center, you likely want to pass the account information captured by the IVR to the call center system. This contextual information is often passed in SIP Headers.

How SIP UUI Header works

With SIP UUI header, your customer will only need to provide their information once. This means you can build workflows that allow you to transfer call-related information between agents in the same or different departments when using SIP Refer.

In the above example, Agent K has transferred contextual information to Agent J about Boris the animal and its prison location, LunarMax. Agent J's screen is now able to show this context.

The below example shows how to send contextual information (multiple parameter & value pairs) as part of the same header:

• X-TestHeader: param1=value1;param2=value2;param3=value3
• <Sip>sip:19165453007@m123.sip.us1.twilio.com?X-TestHeader=123456789%3Bencoding%3Dhex</Sip>

Also, you can send UUI header as it is “user-to-user: 1345;encoding=hex” without having to prepend with prefix “X-”and or you can send with prefix “X-”. UUI header is the only one that you can send without the prefix “X-”.

UUI header can be used in other SIP call scenarios such as:

1. Regular call between UserA and UserB.
2. When the call is redirected or forwarded.

Pricing

SIP Refer is priced at $0.10 a Refer and SIP UUI Header is free.

Learn more on how to use SIP Refer and UUI Header

For more information on how to use SIP Refer for your contact center and how to use it in conjunction with SIP UUI Headers, check out the docs. Want to learn more about UUI Headers? Check out these docs on how to send UUI header in incoming calls and how to receive UUI header from outgoing calls.