Definition

CTI (Computer Telephony Integration)

CTI is the wiring between a phone system and a software application (commonly a CRM) so that calls trigger UI events (screen pops, click-to-dial, call logging) and the CRM can drive call control. Modern CTI runs over WebRTC and SIP rather than serial cables.

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Definition

Computer Telephony Integration (CTI) is the wiring between a phone system and a software application, most commonly a CRM. The application gets call events (incoming call, answered, transferred, ended) and can drive call control (place a call, transfer, conference, hold, hang up). The user experience is a unified surface: calls happen "in the CRM" rather than on a separate device.

The term is older than modern voice infrastructure. In the 1990s it meant a serial cable between a desk phone and a PC. Today it means a WebRTC media path plus an event-and-control API.

What CTI enables in a CRM

The expected affordances:

  • Screen pop. When an inbound call arrives, the matching contact / account / case opens automatically in the CRM, before the rep even says hello.
  • Click-to-dial. Clicking a phone number anywhere in the CRM places the call without the rep dialing manually.
  • Call logging. Every call becomes a CRM activity with the right account, contact, duration, direction, outcome, and (if enabled) a recording link.
  • Call control. The rep transfers, conferences, mutes, and holds from inside the CRM UI rather than reaching for the phone.
  • Disposition codes. Reps tag each call with an outcome (left voicemail, talked to decision-maker, sale closed, etc.) before the call disposition flow closes the activity.
  • Skill-based routing. Inbound calls route to the right rep based on customer segment, account ownership, language, time of day.

Done well, CTI eliminates the friction of bouncing between the phone and the CRM. Done badly, it makes both worse than not having CTI at all.

What modern CTI uses under the hood

The modern CTI stack typically consists of:

  • WebRTC for the actual voice media path in the browser.
  • SIP for telephony signaling between the WebRTC gateway and the carrier or PBX.
  • A real-time events API (WebSocket or SSE) the CRM subscribes to for ringing, answered, hung-up events.
  • A REST control API the CRM uses to place, transfer, and end calls.

For deployments with desk phones, the CTI layer also talks to the phone system (Cisco, Avaya, RingCentral, Mitel, Genesys, etc.) via a vendor-specific TAPI / TSAPI-style adapter, or via the vendor's REST API.

Most cloud-native deployments today are full-WebRTC: the rep's "phone" is a browser tab.

How Factory Labs implements CTI

Factory Labs ships a browser softphone built on Twilio Voice + WebRTC. The CTI surface:

  • Inbound. Incoming calls trigger a screen pop with the matched contact, account, and recent order context. Skill-based routing is configurable per tenant.
  • Outbound. Click-to-dial from any phone number field in the CRM places the call.
  • Activity logging. Every call becomes a CRM activity automatically with duration, direction, recording link (if enabled), and disposition.
  • AI handoff. When the AI voice agent transfers a call to a human rep, the rep gets the call AND the conversation transcript so far, AND the order context the agent pulled.
  • Recording posture per jurisdiction. Recording consent and storage policies are configurable per tenant and per state.

For customers with existing telephony (Cisco, Avaya, RingDNA, Genesys), Factory supports CTI integration against those vendors instead of (or alongside) the Twilio default.

See /integrations/twilio and the telephony docs for the technical detail.

Trade-offs

  • Browser-only CTI. Full-WebRTC means the rep needs the browser tab open. Workaround for high-volume contact centers: a thin desktop wrapper around the same WebRTC stack.
  • Carrier dependencies. Voice quality is bounded by the carrier and the network; CTI cannot solve a bad call path.
  • Legacy PBX integration. Hardest case is integrating with an on-premise PBX that has no modern API. Factory supports several common ones; some niche systems require a partner-built bridge.
  • AI Voice Agent. A common application built on top of CTI.
  • WebRTC. The browser standard for real-time media that modern CTI rides on.
  • SIP (Session Initiation Protocol). The signaling protocol underneath most telephony.

Further reading