IVR routes carry calls where the first voice the recipient hears is recorded or synthesised, rather than a live agent. Press-1 campaigns add a keypad step: "press 1 to speak to someone, press 2 to reschedule". Used properly they are some of the most efficient tools a business has for reminders, surveys, collections and opted-in marketing. Used carelessly they are among the most heavily regulated and complained-about kinds of calls. This guide covers both the engineering and the rules.
Key takeaways
- IVR routes are CLI routes cleared for prerecorded or synthesised voice traffic with keypad responses.
- In the US, prerecorded calls to mobiles need prior express consent, and telemarketing needs prior express written consent.
- Every automated campaign should identify the caller, give a callback number and offer an automated opt-out.
- Use RFC 4733 DTMF, careful answering-machine detection and paced campaigns sized to an agreed CPS ceiling.
- Keep consent records detailed enough to prove when, how and for what each recipient agreed.
On this page
What an IVR or press-1 route is
Technically an IVR route is a CLI route that a carrier has agreed to use for prerecorded or artificial-voice traffic. The audio is generated on your platform (or ours), the call is placed over SIP, and keypad responses travel back as DTMF, either in-band, as RFC 2833 / RFC 4733 telephone-events, or as SIP INFO. When the recipient presses the transfer key, your platform bridges the call to an agent queue or a second number.
Carriers separate IVR traffic from conversational traffic because the pattern is different (many calls, short durations, high simultaneous volume) and because terminating networks and regulators treat automated calls differently. A route that is not cleared for automated traffic can be withdrawn without warning if it starts carrying it.
Campaigns that suit IVR routes
- Appointment reminders for healthcare, automotive service and field engineers, with "press 1 to confirm, 2 to reschedule".
- Payment and collections notices to existing customers, routing to an agent or a secure payment line.
- Customer surveys immediately after a service interaction.
- Service and outage notifications to account holders.
- Opted-in marketing to people who have given the specific written consent your jurisdiction requires.
What these have in common is a pre-existing relationship and an expectation of the call. Campaigns built on purchased lists or contact data without consent are not suitable for IVR routes and are not accepted on CLIRoutes.
Consent, TCPA and DNC
United States
The Telephone Consumer Protection Act (TCPA) requires prior express consent for prerecorded or artificial-voice calls to mobile phones, and prior express written consent when those calls include telemarketing. Informational calls to landlines have narrower requirements, but telemarketing calls with a prerecorded message to residential lines also need written consent. Every prerecorded telemarketing call must identify the caller at the start, provide a callback number and offer an automated opt-out mechanism. The FTC Telemarketing Sales Rule and the National Do Not Call Registry apply on top of this, and many states (Florida, Oklahoma, Washington and others) have stricter versions. US routes also require STIR/SHAKEN attestation, which ties every call back to the originating provider.
United Kingdom and Europe
Under PECR in the UK, automated marketing calls require prior consent specifically for automated calls. Ofcom's persistent misuse policy also covers abandoned and silent calls. In the EU, ePrivacy rules and national implementations (Germany's UWG, France's Bloctel register, Spain's Robinson list) apply. See the country pages for UK IVR routes, Germany and France.
What we ask for
- A description of each campaign: purpose, audience, message script and calling hours.
- How consent was obtained and how it is recorded and retained.
- Your DNC scrubbing process and how opt-outs are honoured across campaigns.
- The CLI you will present, with evidence that you are authorised to use it.
Designing a compliant, effective message
- Identify yourself in the first sentence. "This is Northside Dental with a reminder for Alex." People stay on the line when they know who is calling.
- State the purpose immediately. One reason per call.
- Offer a clear action and an opt-out. "Press 1 to confirm, press 2 to speak to us, press 9 to stop these calls."
- Give a callback number that is staffed or reaches a working IVR during business hours.
- Keep it under 30 seconds before the first keypad prompt.
Present a CLI the recipient can call back, ideally the same number shown in your other communications. A recognisable DID number in the recipient's country typically lifts answer rate and reduces complaints.
Engineering notes: DTMF, AMD and capacity
DTMF
Use RFC 4733 telephone-events (payload type 101 is conventional) and make sure your platform negotiates them in SDP. In-band DTMF is unreliable over compressed codecs such as G.729. If keypresses are lost, check that both sides agreed on the same payload type.
[ivr-trunk]
type=endpoint
context=from-ivr
disallow=all
allow=ulaw,alaw
dtmf_mode=rfc4733
outbound_auth=ivr-trunk-auth
aors=ivr-trunk
from_domain=sip.example-carrier.netAnswering machine detection
For reminders, leaving a message on voicemail is often the desired outcome, so configure AMD to wait for the beep and play a shorter version. Aggressive AMD that hangs up within two seconds creates short calls and silent-call complaints.
Capacity
IVR campaigns are bursty. A list of 20,000 reminders started at 9:00 can require far more CPS than any agent campaign. Agree a CPS ceiling with your carrier and pace the campaign to it. Our CPS sizing guide explains how.
Measuring IVR campaign quality
| Metric | Why it matters | Healthy guidance |
|---|---|---|
| ASR | Reach of the campaign | 35–55% for opted-in reminders |
| Key-press rate | Engagement with the message | Track per script version |
| Opt-out rate | Consent quality and message fit | Low and stable; spikes need review |
| Complaint rate | Route and number reputation | As close to zero as possible |
| Transfer success | Agent queue capacity | Above 95% of key-1 presses |
These figures sit alongside the standard ASR, ACD, PDD and NER metrics in your portal.
Keeping consent records that stand up
Consent is only useful if you can prove it. For each recipient, store when and how consent was given, the exact wording they agreed to, the source (web form, paper, recorded call), the phone number it covers, and any later opt-out. Keep records for at least as long as the limitation period for claims in the recipient's jurisdiction; in the US, TCPA claims can be brought up to four years after a call.
| Field | Example |
|---|---|
| Phone number | +15125550134 |
| Consent captured | 2026-08-19T14:02:11Z |
| Source | Appointment booking form, v3 |
| Consent text | "I agree to receive automated appointment reminder calls at this number." |
| Scope | Informational reminders only |
| Opt-out | None / timestamp and channel |
Honour opt-outs across every campaign, not just the one where the request was made, and process them quickly. The FCC requires revocation requests made by any reasonable means to be honoured, and many other regulators take the same view.
Pacing and calling windows
Spread campaigns across the permitted window instead of starting every call at the first allowed minute. Pacing reduces CPS bursts, keeps transfer queues manageable when recipients press 1, and avoids the clustered call patterns that terminating analytics associate with nuisance calling. Always calculate calling windows in the recipient's local time zone, which in countries such as the United States, Canada and Australia means several zones within one list.
- US federal rule: telemarketing calls only between 8 a.m. and 9 p.m. recipient local time; several states are stricter.
- Retries: limit attempts per number per day and per week; repeated unanswered calls are a common source of complaints.
- Transfers: size the agent queue for your expected key-1 rate so callers who ask to speak to someone are not left waiting.
Example script structure
"Hello, this is Northside Dental calling with a reminder for Alex.
You have an appointment on Thursday the 14th at 3:30 p.m.
Press 1 to confirm. Press 2 to speak to our team about rescheduling.
To stop receiving reminder calls, press 9.
You can also call us back on 020 7123 4567. Thank you."Notice the order: identity, purpose, specific detail, actions, opt-out, callback number. Test two or three versions of the same script and compare key-press rates. Small changes, such as moving the appointment time earlier in the message, often make a measurable difference. Replay the message if no key is pressed within a few seconds, then end the call politely rather than holding the line open.
What IVR routes are not for
IVR routes are not for unsolicited automated marketing, calls to numbers without consent, messages that hide who is calling, or campaigns that ignore opt-outs. Traffic like this is the reason regulators and networks restrict automated calling, and carrying it puts every legitimate sender on the same route at risk. Our Acceptable Use Policy sets out the rules in full, and campaigns are reviewed before activation.
Ready to set up a campaign? Read the IVR routes overview or talk to our compliance team about your use case.
About the author
Priya Natarajan, Compliance Lead
Priya leads customer onboarding, caller-ID authorisation and campaign review. She previously worked on numbering and consumer-protection policy for a European telecoms operator.
Published · Last reviewed