build.allanninal.dev

Part 2 of 7 · Voice agent series ~4 min read

How a call connects

Before any AI hears a word, the call has to find your phone number, ring through, and decide whether you’re open. The moment the caller starts talking is when the AI takes over.

Call routing: greeting, time-of-day check, three possible outcomes A vertical flow with three branches at the bottom. At the top, “Phone rings” representing an inbound call to the business number. An arrow leads down to a Contact flow box that handles the initial greeting and decides what to do next. From the Contact flow, three labeled arrows fan out to three outcome boxes. The left outcome, labeled “after hours”, is the voicemail box where the agent records a short message and a callback number. The middle outcome, labeled “business hours”, is the AI session start — this is where the listener takes over. The right outcome, labeled “known urgent number”, is a direct human transfer that skips the AI entirely. A bottom note reads: by the time the AI hears anything, the call has already been screened for time-of-day and direct-transfer rules. Phone rings caller dials your number Contact flow short greeting, checks time + caller after hours business hours known urgent Voicemail short message, captures a callback number AI session listener takes over, conversation begins Direct transfer skips the AI, rings a human By the time the AI hears anything, the call has already been screened for time-of-day and direct-transfer rules.
Fig 2. Three ways a call can go. The AI only handles the middle path; the other two run on simple rules.

The phone number itself

You need a real phone number callers can dial. The cloud lets you claim one for a flat monthly fee — the same way you’d rent a phone line from a telco, but pay-as-you-go for the actual minutes used.

If you already have a business number on a regular phone plan, you can usually port it in. Most callers don’t notice the change — the number stays the same, the line just answers smarter.

What the contact flow does first

The moment the call connects, a short greeting plays — something like “Thanks for calling [your business]. One moment.” While the caller hears that, the cloud quietly checks two things in the background:

  • What time is it? Compares against your business hours from the knowledge file.
  • Who’s calling? Looks at the caller’s number against a small VIP list (existing customers, urgent contacts, your top five accounts).

Both checks finish before the greeting does. The next step happens silently.

Three ways a call can go

Based on those two checks, the contact flow chooses one of three paths.

  • After hours. The caller hears your closed-hours message and gets a chance to leave a voicemail with a callback number. You see it the next morning — the AI never runs.
  • Business hours. The greeting ends; the listener takes over. From here, the rest of the series is what happens.
  • Known urgent number. If the caller is on your VIP list, the AI is skipped entirely — the call is transferred straight to you. Important customers don’t talk to a robot.

Why screen before the AI runs

Two reasons.

First, cost. Every minute the AI is running, it’s spending money on listening, deciding, and speaking. After-hours voicemail is essentially free; routing a regular customer through the AI is a waste.

Second, trust. Some callers don’t want to talk to a robot, full stop. Building a quick way to skip the AI for VIPs (or for a particular dialed extension) means the agent is never in the way of someone who needs you immediately.

In plain words

The AI is one of three possible paths, not the only path. Time-of-day decides whether you’re open; the caller’s number decides whether they get straight through to you. Everything else flows into the AI session — which is where the rest of the series picks up.

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