2BKXU-S280FInforTab Slim

Rev 1/26/2023 PARTRON ESL Co., Ltd. 829-836, 42, Changeop-ro, Sujeong-gu, Seongnam-si, Gyeonggi-do, South Korea Federal Communications Commission Authorization and Evaluation Division 7435 Oakland Mills Road Columbia, MD 21046 USA Date: 04-17-2026 Ref: Attestation Statements Part 2.911(d)(7) Filing Grantee Code: 2BKXU FCC ID: 2BKXU-S280F Applicant FRN: 0035929710 [PARTRON ESL CO., Ltd.] (“the applicant”) certifies that, as of the date of the filing of the application, [FCC US Agent, LLC] is our designated U.S. agent for service of process for the above referenced Grantee Code. [PARTRON ESL CO., Ltd.] accepts to maintain an agent for no less than one year after the grantee has terminated all marketing and importation or the conclusion of any Commission-related proceeding involving the equipment. [FCC US Agent, LLC] accepts, as of the date of the filing of the application, the obligation of the designated U.S. agent for service of process for the above referenced Grantee Code. Designated U.S. Agent Information: Name: FCC US Agent, LLC U.S. Agent FRN: 0033402884 Address: 3722 Illinois Avenue Saint Charles, IL 60174 United States Contact Person: Tim Payne Tel.: (708) 571‐3148 Email: [email protected] Sincerely, [PARTRON ESL Co., Ltd.] FCC US Agent, LLC [taehoon kim] Tim Payne

Rev 1/26/2023 PARTRON ESL Co., Ltd. 829-836, 42, Changeop-ro, Sujeong-gu, Seongnam-si, Gyeonggi-do, South Korea Federal Communications Commission Authorization and Evaluation Division 7435 Oakland Mills Road Columbia, MD 21046 USA Date: 04-17-2026 Ref: Attestation Statements Part 2.911(d)(5)(i) Filing FCC ID: 2BKXU-S280F [PARTRON ESL Co., Ltd.] (“the applicant”) certifies that the equipment for which authorization is sought is not “covered” equipment prohibited from receiving an equipment authorization pursuant to section 2.903 of the FCC rules. [PARTRON ESL Co., Ltd.] (“the applicant”) certifies that the equipment for which authorization is sought does not include cybersecurity or anti-virus software produced or provided by Kaspersky Lab, Inc. or any of its successors and assignees, including equipment with integrated Kaspersky Lab, Inc. (or any of its successors and assignees) cybersecurity or anti-virus software pursuant to DA-24-886 and KDB 986446 D01 Covered Equipment Guidance section B(2a). Device is inherently compliant based on hardware limitations or software controls. or A Software Bill of Materials (SBOM) is provided to the TCB for review, and The end-user or third parties cannot install additional software on this device. Sincerely, taehoon kim Rev 1/26/2023 PARTRON ESL Co., Ltd. 829-836, 42, Changeop-ro, Sujeong-gu, Seongnam-si, Gyeonggi-do, South Korea Federal Communications Commission Authorization and Evaluation Division 7435 Oakland Mills Road Columbia, MD 21046 USA Date: 04-17-2026 Ref: Attestation Statements Part 2.911(d)(5)(ii) Filing FCC ID: 2BKXU-S280F [PARTRON ESL Co., Ltd.] (“the applicant”) certifies that, as of the date of the filing of the application, the applicant is not identified on the Covered List (as a specifically named entity or any of its subsidiaries or affiliates) as an entity producing “covered” equipment. Sincerely, taehoon kim

PARTRON ESL Co., Ltd. 829-836, 42, Changeop-ro, Sujeong-gu, Seongnam-si, Gyeonggi-do, South Korea Date: 04/17/2026 Federal Communications Commission Authorization and Evaluation Division 7435 Oakland Mills Road Columbia, MD 21046 USA Request of Confidentiality FCC ID: 2BKXU-S280F To Whom It may Concern: Pursuant to Sections 0.457 and 0.459 of the Commission`s Rules(CFR 47), and Section 552 (b) (4) of the Freedom of Information Act, PARTRON ESL Co., Ltd. hereby requests confidentiality and treatment of certain information accompanying this application. The materials contain trade secrets and proprietary information not customarily released to the public. The public disclosure of these matters might be harmful to the Applicant and provide unjustified benefits to its competitors. We are also hereby request Short-Term Confidentiality for 180 days after the grant as outlined in Public Notice DA 04-1705. This provision will give PARTRON ESL Co., Ltd. temporary confidentiality of commercially sensitive information prior to product release. The requested permanent and Short-Term Confidential exhibits are listed as follows: PERMANENT & SHORT-TERM CONFIDENTIAL LIST Exhibit Description PERMANENT 1 Block Diagram 2 Schematics 3 Part Lists 4 Operation Description 5 Part Location SHORT-TERM 6 Internal Photos 7 External Photos 8 Test-Setup Photos 9 User Manual The Applicant understands that pursuant to Rule 0.457, disclosure of this application and all accompanying documentations, where applicable, will not be public before the date of the Grant for this application. Sincerely, Contact Name: taehoon kim Title: Senior Researcher

PARTRON ESL Co., Ltd. 829-836, 42, Changeop-ro, Sujeong-gu, Seongnam-si, Gyeonggi-do, South Korea Date: 04/17/2026 Federal Communications Commission Authorization and Evaluation Division 7435 Oakland Mills Road Columbia, MD 21046 USA Letter of Authorization We, the undersigned, hereby authorize Geunki Son of Dt&C Co., Ltd. to act on our behalf in all manners relating to application for equipment authorization for FCC ID: 2BKXU-S280F including signing of all documents relating to these matters. Any and all acts carried out by Geunki Son of Dt&C Co., Ltd. on our behalf shall have the same affect as acts of our own. This authorization is valid until further written notice from PARTRON ESL Co., Ltd. “I, the undersigned, hereby certify that we are not subject to a denial of federal benefits, that includes FCC benefits, pursuant to Section 5301 of the Anti-Drug Abuse Act of 1988, 21 U.S.C. 853(a).” Sincerely, Contact Name: taehoon kim Title: Senior Researcher

Label Location Battery cover FCC ID: 2BKXU - S280F

FCC ID: RF featureMode Test separation distance (mm) ANT Gain (dBi) Max. power with tune-up tolerance (dBm) Note1 Max. power with tune-up tolerance (mW) Power thresholds SAR test exclusion thresholds Zigbee O-QPSK (250 kbps)2405.00~2480.005.02.89-6.000.25120.083.00 Note1. Conclusion : SAR evaluation for general population exposure conditions by measurement or numerical simulation is not required KDB 447498 D01 clause 4.3.1 Step 1) SAR test exclusion thresholds for 100MHz to 6GHz at test separation distances ≤ 50 mm [ ( max. power of channel, including tune-up tolerance, mW ) / ( min. test separation distance, mm ) ] · [ √f(GHz) ] ≤ 3.0 for 1g SAR and ≤ 7.5 for 10g extremity SAR Sample Calculation = [ ( 0.2512mW / 5mm ) ] X [ √2.48GHz ] = 0.08 Note. The calculation result was rounded to two decimal place for comparison. 2BKXU-S280F Please refet to the operation description for Max Tune-up power. Transmitting Frequency(MHz) Standalone SAR test exclusion considerations

Report No.: DRTFCC2604-0038(1) FCC ID: 2BKXU-S280F This test report is prohibited to copy or reissue in whole or in part without the approval of Dt&C Co., Ltd. TRF-RF-238(07)250909 Pages: 2 / 36 Test Report Version Test Report No. Date Description Revised by Reviewed by DRTFCC2604-0038 Apr. 17. 2026 Initial issue SeokHo Han JaeJin Lee DRTFCC2604-0038(1) Apr. 22. 2026 Revise test note 4 in section 5.5.3 SeokHo Han JaeJin Lee Report No.: DRTFCC2604-0038(1) FCC ID: 2BKXU-S280F This test report is prohibited to copy or reissue in whole or in part without the approval of Dt&C Co., Ltd. TRF-RF-238(07)250909 Pages: 3 / 36 Table of Contents 1. General Information .................................................................................... 4 1.1. Description of EUT .......................................................................................................... 4 1.2. Declaration by the applicant / manufacturer ................................................................ 4 1.3. Testing Laboratory .......................................................................................................... 5 1.4. Testing Environment ....................................................................................................... 5 1.5. Measurement Uncertainty............................................................................................... 5 1.6. Test Equipment List ........................................................................................................ 6 2. Test Methodology ........................................................................................ 7 2.1. EUT Configuration ........................................................................................................... 7 2.2. EUT Exercise .................................................................................................................... 7 2.3. General Test Procedures ................................................................................................ 7 2.4. Instrument Calibration .................................................................................................... 7 2.5. Description of Test Modes.............................................................................................. 7 3. Antenna Requirements ............................................................................... 8 4. Summary of Test Results ........................................................................... 9 5. Test Result ................................................................................................. 10 5.1. Maximum Peak Conducted Output Power .................................................................. 10 5.1.1. Test Setup .................................................................................................................. 10 5.1.2. Test Procedures ........................................................................................................ 10 5.1.3. Test Results ............................................................................................................... 10 5.2. 6 dB Bandwidth ............................................................................................................. 13 5.2.1. Test Setup .................................................................................................................. 13 5.2.2. Test Procedures ........................................................................................................ 13 5.2.3. Test Results ............................................................................................................... 13 5.3. Power Spectral Density ................................................................................................. 16 5.3.1. Test Setup .................................................................................................................. 16 5.3.2. Test Procedures ........................................................................................................ 16 5.3.3. Test Results ............................................................................................................... 16 5.4. Unwanted Emissions (Conducted) .............................................................................. 19 5.4.1. Test Setup .................................................................................................................. 19 5.4.2. Test Procedures ........................................................................................................ 19 5.4.3. Test Results ............................................................................................................... 20 5.5. Unwanted Emissions (Radiated) .................................................................................. 28 5.5.1. Test Setup .................................................................................................................. 29 5.5.2. Test Procedures ........................................................................................................ 29 5.5.3. Test Results ............................................................................................................... 30 5.6. AC Power-Line Conducted Emissions ........................................................................ 31 5.6.1. Test Setup .................................................................................................................. 31 5.6.2. Test Procedures ........................................................................................................ 31 5.6.3. Test Results ............................................................................................................... 31 APPENDIX I .................................................................................................... 32 APPENDIX II ................................................................................................... 33 APPENDIX III ..…

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1 S280F RF Radiated data Prepared by Checked by Approved by SJ KIM YS LEE TH KIM 2026.01.23. 2 Table of Contents 1. Frequency Band ............................................................................................................................................................... 3 1-1. Measurement Engineer ................................................................................................................................. 3 1-2. VSWR ........................................................................................................................................................................ 3 1-3. Efficiency & Gain ............................................................................................................................................... 4 1-4. 3D Radiated Pattern ........................................................................................................................................ 5 2. TEST METHOD ................................................................................................................................................................. 6 2-1. Measurement information ........................................................................................................................... 6 2-2. Return Loss & VSWR Test ............................................................................................................................ 6 3 1. Frequency Band Mode Frequency Band (MHz) Zigbee 2,400 ~ 2,500 - 1-1. Measurement Engineer - Connect the device under test and required test equipment (Network analyzer). Measuring VSWR and frequency. Measurements include the magnitude and phase of both the vertical and horizontal components of the 3-D antenna pattern of actual hardware in an anechoic chamber (Partron). all measurements are made with antennas installed. - Frequency, VSWR measurement - Gain measurement - Co-Polarization, Cross-Polarization Meaning - Co-Polarization : When Radiated Vertical and Horizontal Polarization in Source Ant. Co-Polarization is Higher Polarization that is Ave. Gain Value - Cross-Polarization : When Radiated Vertical and Horizontal Polarization in Source Ant. Co-Polarization is Lower Polarization that is Ave. Gain Value Antenna gain measurements were performed in a full anechoic chamber. The EUT was placed on a turntable of the chamber. During the test, the EUT was rotated through 360° and the measurement antenna height and polarization were varied to maximize the received emission level. The chamber walls, ceiling, and floor were lined with RF absorbing material to minimize reflections and simulate free-space conditions. 4 1-2. VSWR 1-3. Efficiency & Gain 5 1-4. 3D Radiated Pattern 2400MHz 2445MHz 2485MHz 6 2. TEST METHOD 2-1. Measurement information Description Manufacturer Model Calibration date Network Analyzer Anritsu ME7848A 25.09.20 Horn Antenna SCHWARZBECK BBHA 9120 LF 25.07.21 2-2. Return Loss & VSWR Test Figure 1: Testing with RF Chamber Measurement facility: Partron, 3D Chamber 7 3.Antenna Dimension Manufacturer: PartronESL Address :829-836,42,Changeop-ro,Sujeong-gu, Seongnam-si,Gyeonggi-do, SouthKorea