CallClock vs Ondaris
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
CallClock
Schedule calls to act as alarms or reminders for various occasions. Simulate incoming calls to politely exit unwanted social situations. Customize caller ID, ringtones, and call content for a personalized experience.
- Schedule calls as alarms
- Simulate incoming calls
- Customizable caller display
- Customizable call content
- Multiple time setting methods
- Text-to-speech functionality
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You can schedule a call as alarm clock / reminder. You can also use it to simulate a phone call, to simulate anyone calling you anytime, to help you get out of a party or date that you don't want to continue! Multiple time setting methods to call you and send reminders anytime: Special Date \ Every Day \ Every Workday \ Every Week \ Every Month Customized incoming caller display: Name / Avatar / Poster / Ringtone Customized call content: Recorded sounds / Text to Speech / Imported sounds Paid service terms: http://www.vcclock.com/vc/static/termsConditions Privacy policy: http://www.vcclock.com/vc/static/privacy
Ondaris
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Ondaris is a calculation workspace for communications, optics and photonics: for engineers, students, researchers, lecturers and technicians who need the number and the working behind it. Enter your parameters once and explore the whole system. Change the frequency and the wavelength, path loss, antenna aperture, Fresnel radius and Doppler shift all follow. Every calculation shows its work. Tap through to the equation, what each symbol means, what the model assumes, where it stops being valid, and which document it came from. Export a PDF that carries all of it, so the person reading your report can check you. WHAT IS INSIDE 66 calculators in five groups. Converters: frequency and wavelength; W, dBm and dBW; ratio and decibels; VSWR, return loss and match; propagation delay. RF and microwave: free-space path loss, link budget, microstrip line, Fresnel clearance, EIRP and power flux density, antenna gain and aperture, thermal noise, cascaded noise figure, receiver SNR and G/T, Shannon capacity, Doppler shift, rain attenuation, antenna patterns, arrays and Yagis, RF exposure limits, multipath fading, channel dispersion and coherence, phase noise to jitter, Allan deviation, and a Smith chart with L-network synthesis. Link performance: bit error rate for M-PSK, square M-QAM and on-off keying, receiver sensitivity, fading channel capacity, the deterministic eye diagram, and how long a bit error rate test must run. Optical: photon energy and rate, refraction and reflection at an interface, laser diode, detector responsivity, optical receiver SNR, APD and optimum gain, optically preamplified and coherent receivers, Gaussian beams, micro-ring resonator, fixed and flexible DWDM grids, FSO link budget, and FSO scintillation, turbulence fading and pointing error. Fiber: power budget, V-number and guided modes, multimode modal bandwidth, mode field and joint loss, chromatic and polarisation mode dispersion, nonlinearity, four-wave mixing, OSNR of an amplified chain, and three measurements: dispersion fitted to group delay, OTDR splice loss, and OSNR on a spectrum analyser. HOW IT WORKS Every topic opens with the question it answers, why it matters and what the number means. Guided pathways walk you through designing a radio, free-space optical or fiber link, and measuring one. Strict units: GHz or MHz, dBm or watts, kilometres or feet, all converted to SI, so the answer never depends on how you typed it. Live recalculation, and plots you can scrub with the operating point marked. Reverse solving on 62 of the 66 calculators: set the answer you need and the input follows. Every answer ranks its inputs by influence, and turns tolerances you enter into an uncertainty on the result. Projects that share parameters across calculators, with side-by-side scenario comparison. PDF, CSV, LaTeX, Python and MATLAB export, carrying the assumptions, the validity range and the source clause with them. Built for VoiceOver and Dynamic Type throughout: charts are spoken, not just drawn. Every calculation runs offline. No account required. The only time Ondaris uses the network is to fetch the Pro price from the App Store and to buy, check or restore a purchase. WHAT IT IS NOT Ondaris is a calculation bench, not a simulator. Its models state their assumptions, and are closed-form where one exists and computed numerically, with independent checks, where it does not. It does not do full-wave electromagnetics, ray tracing or end-to-end system simulation. Each formula carries its review status; 30 are approved by SCOPT Inc., with their limitations stated. That is an engineering review by the publisher, not certification by any standards body or test house. No advertising. No tracking. No chatbot. FREE AND PRO Every formula page is free to read, and 28 calculators are free to use. Ondaris Pro, a one-time purchase, adds 38 specialist calculators, reverse solving beyond the converters, unlimited projects and export. Developed by SCOPT Inc.
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Verdict
The clearest difference is update cadence: Ondaris at every 2 weeks against CallClock's every 2 months. CallClock's advantage is iOS requirement (12.2 vs 16.4). On price, ads, in-app purchases and device support there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Both are free to download. CallClock sells 6 in-app purchases, starting at $0.99 per month and Ondaris sells 1 one-off in-app purchase. Whichever you choose, the download price is not the number that matters.
CallClock ships an update every 2 months, Ondaris every 2 weeks. The most recent releases landed on October 27, 2026 and October 26, 2026 respectively.
| Parameter | CallClock | Ondaris |
|---|---|---|
| Price | Free | Free |
| Rating | 4.7 (15 ratings) — better | — |
| Positive reviews | 83.3% of reviews | — |
| Number of ratings | 15 — better | — |
| Update frequency | Every 2 months | Every 2 weeks — better |
| Ads | No | No |
| In-app purchases | Yes | Yes |
| Monetization | Free with in-app purchases | — |
| Devices | iPhone, iPad, iPod — better | iPhone, iPad |
| Requires iOS | 12.2 — better | 16.4 |
| Further details — not scored | ||
| Size | 27 MB | 52 MB |
| Age rating | 4+ | 4+ |
| Developer | 博 成 | SCOPT Inc. |
In-app purchases
CallClock
- Basic-Monthly$0.991 Month
- Standard-Monthly$2.991 Month
- Basic-Yearly$9.491 Year
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- Premium-Monthly$12.991 Month
- Standard-Yearly$34.991 Year
- Premium-Yearly$154.991 Year
Ondaris
- Ondaris Pro$12.99









