Use cases · VoLTE & Voice
VoLTE and voice testing with real calls on live networks
VoLTE testing confirms that a SIM registers with the operator's IMS, places calls on the expected bearer and connects in a reasonable time — at home and while roaming. SimCheck.ai places real calls from real modems on live networks and reports IMS registration state, the bearer used (VoLTE, VoNR or circuit-switched), call setup time, talk time and outcome, with a recording of every call.
Voice is assumed to work, until it doesn't
Voice used to be the easy part: if a phone had signal, it could call. As 2G and 3G networks are switched off, voice depends on VoLTE or VoNR — and that depends on IMS registration, the right IMS settings on device and network, and, abroad, on VoLTE roaming support between operators. When any piece is missing, a device can show full LTE bars and still be unable to call, or try to fall back to a circuit-switched network that no longer exists.
Most voice failures are invisible to data-centric monitoring. A roamer who can't call, an MVNO whose IMS configuration is wrong on one partner, a calling-card platform whose prompts changed — none of these show up in an attach check. Verifying voice means placing real calls on the real network and checking how they were carried and how they ended.
How voice testing works
- 1
Pick the SIM and network
Choose the eSIM profile and location, and optionally force the radio technology or the operator by PLMN to test a specific partner. The profile's MSISDN is used as the caller number when the SIM doesn't report one.
- 2
Place a real call
The Voice Call Check dials a real number over the live network and holds the call for its talk time.
- 3
Read what happened
See IMS registration state, the bearer, setup time, talk time and the outcome — Connected, Busy, No answer or Rejected — and play back the recording.
- 4
Track it over time
Schedule voice checks per market and partner, and follow call-setup time, drop rate and IMS-registered rate in reports.
What voice testing covers
IMS registration
See whether the SIM was registered with IMS for the call — the first thing to check when VoLTE fails.
Bearer detection
Each call reports whether it was carried as VoLTE, VoNR or circuit-switched, so silent fallbacks become visible.
Setup time and outcome
Call setup time, talk time and a plain outcome separate a network problem from someone not picking up.
Call recordings
Every real call attaches its audio to the run, playable from the results page.
SMS delivery
The SMS Test sends a message and checks its delivery report on the same SIM and network.
Calling Card Check with an AI agent
An AI agent dials a calling-card access number, listens to the prompts, enters the PIN, dials the destination and returns a transcript with a pass/fail verdict.
Manual calls when you need them
Test Like A Mobile gives you a dialer with DTMF tones and a messaging app on the real modem for exploratory testing.
Voice reports
Measure call-setup time, drop rate, voice MOS and IMS-registered rate, and review every AI-agent call in a call-record report.
What to test in a VoLTE program
| Check | What failure looks like | How to test it |
|---|---|---|
| IMS registration | LTE attach succeeds but calls fail | Voice Call Check reports IMS state |
| Bearer | Calls go circuit-switched instead of VoLTE, or fail where 2G/3G is gone | Bearer per call; force LTE or 5G SA |
| Call setup | Long delay after dialing | Setup time per call, trended in reports |
| Call completion | Calls rejected or dropped | Outcome per call; drop rate in reports |
| Roaming voice | No voice on a partner network | Force the visited operator by PLMN and call |
| VoNR | 5G SA calls don't stay on NR | Force 5G SA and check the reported bearer |
| SMS | Messages not delivered | SMS Test with delivery status |
| IVR and calling cards | Prompt or PIN flow broken | Calling Card Check with transcript |
Voice while roaming
Roaming voice is where most surprises live. VoLTE roaming needs both the home and visited operators to support it, and many agreements still rely on circuit-switched voice in the visited network. As 2G and 3G networks close, a roamer whose agreement doesn't cover VoLTE can end up with data but no voice at all.
To check it, force the visited operator by PLMN, place a Voice Call Check, and look at two fields: IMS registration and bearer. A call that connects over circuit-switched voice tells you the partner still runs a legacy network; a call that fails without IMS registration points at the VoLTE roaming arrangement. Run the same check on every partner and track it alongside data in roaming testing. On 5G SA networks, the same check shows whether calls are carried as VoNR — see 5G SA testing.
Calling cards and IVR flows
Calling-card and IVR services are hard to automate because the test has to listen. The Calling Card Check hands that job to an AI agent: it dials the access number, listens to the prompts, enters the PIN, dials your destination and reports a transcript plus a pass/fail against the goal you described.
The AI agent call record report lists every call with its A-number, B-number, outcome and talk time, and opens the transcript for each. Schedule the check to catch a broken prompt sequence before your customers do, or run it by hand from Test Like A Mobile when you need to listen yourself.
Frequently asked questions
What is VoLTE testing?
VoLTE testing verifies that a device and SIM register with the operator's IMS and place voice calls over LTE, with acceptable setup time and call completion. It typically covers IMS registration, the bearer used, call setup, call outcome and behavior while roaming.
How do you test VoLTE on a live network?
Put the SIM in a VoLTE-capable device on the target network, confirm IMS registration, place a real call, and check which bearer carried it, how long setup took and how it ended. SimCheck.ai's Voice Call Check reports all of these and records the call.
Why does VoLTE fail when roaming?
Usually because VoLTE roaming isn't enabled between the home and visited operators, or IMS settings don't match. The device then falls back to circuit-switched voice if the visited network still has it — or has no voice at all where 2G and 3G have been switched off.
Can you test VoNR on 5G SA?
Yes, where the modem and network support it. Force 5G SA and run the Voice Call Check; the result reports whether the call was carried as VoNR, VoLTE or circuit-switched. The Modem Catalogue shows which modules list VoNR support.
Are test calls recorded?
Yes. Every test that places a real call, including AI-agent calls, attaches a recording to the run, playable from the results page.
Can I test SMS as well as voice?
Yes. The SMS Test sends a message and checks the network's delivery report, and Test Like A Mobile lets you send and receive SMS by hand on the same modem.
Keep exploring
- GlossaryVoLTE (Voice over LTE)VoLTE (Voice over LTE) carries phone calls as IP packets over 4G using IMS, replacing 2G/3G circuit-switched voice. Learn how it works and how to test it.
- GlossaryIMS (IP Multimedia Subsystem)IMS (IP Multimedia Subsystem) is the 3GPP SIP-based core that delivers voice, video and messaging over IP for VoLTE, VoNR, Wi-Fi Calling and RCS.
- Use casesRoaming TestingLock tests to each partner by PLMN, verify data, SMS and voice, and track every pair in a roaming matrix.
- Use cases5G SA TestingForce 5G SA or NSA on real 5G modems, verify registration, and measure throughput and latency — at home and roaming.
- PlatformTest Like A MobileAn interactive phone on a real modem with dialer, SMS and a real Chromium browser running over the cellular link.
- SolutionseSIM Testing for Mobile Operators & MNOsAutomated eSIM, roaming, VoLTE and 5G testing for mobile operators. Validate SGP.22 and SGP.32 profiles and roaming partners on live networks with AI.
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