Track 09 · Systems & unit costLesson 04 of 11
Voice in the contact centre
Join real calls: telephony, transfers and contact-centre platforms.
- Specialisation · Healthcare
- Specialisation · Customer experience & voice
- 40 min read
- 75 min hands-on
- Pro
What you'll be able to do
01- You can explain how a call reaches your agent: PSTN, carrier, number, SIP trunk, telephony platform, WebSocket.
- You can choose between TwiML-only, ConversationRelay and Media Streams for a given control and compliance need.
- You can design a warm transfer that carries context into a human queue and pops the right record, and say when SIP REFER applies.
- You can implement recording consent, PCI pause-and-resume and DTMF fallback as deterministic rules, not prompt instructions.
- You can explain TCPA exposure after FCC 24-17 and STIR/SHAKEN for outbound calls, and report containment, transfer rate and AHT honestly.
Before you start
- Voice agents and conversation design: STT, TTS, turn-taking and latency budgets.
- Handing off to a person, well: triggers, context packaging, return paths.
- Agents inside CRM, ERP and ITSM: writing the Case.
- Finding and masking personal data: tokenising member IDs.
- Background: HTTP webhooks, WebSockets, basic XML.
The short version
A production voice agent joins someone else's phone system. Calls arrive over the PSTN on a number the customer owns, through a carrier or SIP trunk, into a platform such as Twilio, and only then reach your code as webhooks and a WebSocket. The audio is 8 kHz G.711, callers press keys as well as talk, and calls the agent cannot finish must reach a human in a contact centre that already owns routing, recording and the screen pop. Consent, PCI, TCPA and transfer rules are enforced in deterministic code.
- Telephony constrains the voice stack: design for 8 kHz audio and keypad fallback from day one.
- Pick the Twilio integration level by who owns turn-taking and audio.
- Warm transfer: the packet goes to the system of record, only a reference rides in telephony metadata.
- Consent, PCI and TCPA rules live in the call-flow state machine, where tests can prove them.
- Containment counts calls the agent resolved, not calls that simply did not transfer.
Practise this in the lab
Pro lesson
The rest of this lesson is in Pro.
The mental model, worked example, field note, failure table, exercise and self-check, with the voice tutor.
- Every stage and specialisation, in full
- Every lab and every role project
- Halden weeks 2–10, on your record
- Every drill, live in the playground
- All solutions, plus the server judge
- Lab Assistant and every Teach with AI