The Real Reason PRC Requires See-Through Sci-Cals
Ever wondered why CELE reviewees are required to use scientific calculators with see-through plastic backs? From a viral ₱100,000 SIM-card calculator caught in 2018 to the "smoked casing" cheating incidents of April 2024, here is the true story behind the PRC calculator ban.
Walk into any civil engineering review center today and you will notice something strange on the desks: nearly every reviewee is practicing on a scientific calculator with a crystal-clear, see-through plastic back.
To freshmen and outsiders, it looks like a nostalgic Y2K aesthetic trend. To board exam veterans and the Professional Regulation Commission (PRC), however, that transparent plastic shell is a frontline defense against one of the wildest high-tech cheating scandals in Philippine licensure history.
The ₱100,000 "Texting" Calculator
The crackdown began in April 2018 when the PRC issued Memorandum Circular No. 2018-01, abruptly banning the iconic Casio fx-991ES and Casio fx-991ES Plus across all board exams. At the time, many reviewees assumed the ban was purely due to the calculator's fast built-in functions (SHIFT + SOLVE, matrices, and numerical integration).
However, the circular contained a telling instruction directing proctors to check for "improvised/tampered" calculators containing "audio-visual features."
Months later, during the November 2018 Civil Engineering Licensure Examination (CELE), a viral confiscation exposed what was really happening behind closed doors. Examination personnel caught an examinee using a heavily modified Casio calculator that had been gutted and retrofitted with a hidden SIM card slot and GSM receiver—a custom piece of contraband allegedly sold on the black market for up to ₱100,000.
From the outside, the unit looked and calculated like an ordinary scientific calculator. Underneath its opaque plastic shell, however, custom circuitry allowed an outside syndicate to transmit exam answers via text message directly onto the calculator’s LCD screen while the examinee pretended to solve problems.
The May 2019 Syndicate & The First 570ES Plus Ban
After the 991ES Plus was outlawed in 2018, thousands of civil engineering reviewees switched to its twin model, the Casio fx-570ES Plus, which shared the exact same processor and keypad layout minus the solar panel. Naturally, the cheating syndicates switched models too.
During the May 2019 CELE, room watchers and proctors once again intercepted examinees using tampered Casio fx-570ES and fx-570ES Plus units modified into covert communication devices.
Following formal incident reports from the testing centers, the Professional Regulatory Board of Civil Engineering (PRB-CE) released Resolution No. 02 (Series of 2020). In the resolution, the Board explicitly placed on public record that "unscrupulous groups [were] supplying tampered calculators with SIM card to examinees thereby encouraging cheating during the examinations," officially banning the fx-570ES and fx-570ES Plus from the CELE.
The 2023 "Transparent Casing" Compromise—And the April 2024 Relapse
Banning the entire ES Plus lineup left civil engineering examinees in a tough spot, as most of the remaining calculators on the PRC’s older approved list lacked the natural textbook display and algebraic functions needed for complex structural and geotechnical equations.
In the first quarter of 2023, calculator manufacturers and distributors pitched a hardware solution to the Board: transparent and smoked-type casings. The logic was straightforward—if proctors could see straight through the plastic body into the green circuit board, any illegally soldered SIM card slot, extra battery pack, or receiver antenna would be spotted immediately during pre-exam inspection.
Under Board Resolution No. 09 (Series of 2023), the PRB-CE agreed to a trial run for the April 2024 CELE, allowing four popular calculators provided they had transparent or smoked casings:
Casio fx-570ES Plus (with transparent/smoked casing)
Canon F-789SGA (with transparent casing)
Sharp EL-W531TH-WH (with transparent casing)
Olympia ES-570ES Plus (with transparent casing)
It took only one board exam for cheaters to ruin the compromise.
During the April 2024 CELE, proctors caught examinees exploiting the dark tint of the "smoked" casing on the Casio fx-570ES Plus. Because the smoked plastic was dark enough to obscure the internal components unless held directly against a bright light, syndicates still managed to slip modified communication circuits inside the units.
By May 2024, the Board had seen enough. Through Resolution No. 05 (Series of 2024), the PRB-CE permanently banned the Casio fx-570ES Plus—with or without a transparent or smoked casing—from the Civil Engineering board exam.
What Happens When an Examinee Gets Caught?
Under PRC Memorandum Order No. 57 (Series of 2020) and PRB-CE Resolution No. 05 (Series of 2024), room watchers have the authority to inspect an examinee's calculator before the test begins and at any point while the exam is in progress.
If a proctor spots a broken seal, an unusual internal wire, or an unauthorized model:
Immediate Confiscation: The calculator is seized on the spot as physical evidence.
Official Incident Report: The room watcher logs the violation in an Examination/Incident Report submitted directly to the Board of Civil Engineering and the PRC Legal Division.
Cancellation & Debarment: Bringing a tampered communication device constitutes severe examination fraud, resulting in the cancellation of the examinee's test papers, administrative investigation, and perpetual disqualification from taking PRC licensure examinations.
Current CELE Calculator Rules to Remember
If you are preparing for the upcoming Civil Engineering Licensure Examination, make sure you don't get disqualified over a hardware technicality:
Clear Casing is Mandatory for the "Big Three": The Canon F-789SGA, Sharp EL-W531TH-WH, and Olympia ES-570ES Plus are strictly allowed only if they have a clear transparent casing.
No Casio fx-570ES Plus: Even if your Casio fx-570ES Plus has a completely clear custom back cover, it is prohibited in the CELE. (Lower-tier models like the Casio fx-350ES Plus and fx-82ES Plus remain on the approved list without a clear-case requirement).
One Calculator Policy: You may only bring one (1) approved non-programmable calculator inside the testing room. Borrowing, lending, or swapping units mid-exam is strictly forbidden.
Pre-Exam Reset: All calculators are physically inspected and must be memory-reset in front of the proctor before the exam starts.
Sources & Links
PRC September 2026 CELE Official Examination Program (Contains the Full Text of PRB-CE Resolution No. 05, s. 2024 & PRC Memo Order No. 57, s. 2020 Inspection Rules):https://www.prc.gov.ph/sites/default/files/exam%20program%20Sept%202026%20(CE).pdf
PRC Board of Civil Engineering Resolution No. 05 (Series of 2024) — Removing the Casio fx-570ES Plus After the April 2024 Smoked-Casing Incident Reports:https://www.prc.gov.ph/sites/default/files/Civil%20Engineer%202024-05%20published.pdf
PRC Board of Civil Engineering Resolution No. 02 (Series of 2020) — Documenting the May 2019 Tampered SIM-Card Calculator Syndicate:https://www.prc.gov.ph/sites/default/files/2020-02%20Published.PDF
PRC Public Advisory on the Exclusivity of Allowable Calculators (Commission Resolution No. 1809, s. 2024):https://www.prc.gov.ph/article/public-advisory-list-allowable-calculators-during-licensure-examinations
PhilNews Report on the Viral ₱100,000 Customized Calculator with SIM Card Caught During the Nov 2018 CE Board Exam:https://philnews.ph/2018/11/14/customized-calculator-w-sim-caught-during-civil-engineer-board-exam/
Philstar Report on the Initial 2018 PRC Calculator Ban (MC No. 2018-01):https://www.philstar.com/nation/2018/04/26/1809641/prc-bans-2-calculator-models-during-licensure-exams
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