XEN-CK78CK78

How to pair the CK series Bluetooth Keyboard with PC 1. Go to “Setting ” in the Windows and select “Bluetooth and other device”, select “add Bluetooth or other devices” 2. In the prompt out window, select “Bluetooth” 3. Pressing “Fn + ” to switch the keyboard into Bluetooth pairing mode, indicator LED will flash. 4. On the PC side, in the prompt out window, the PC should be able to find a device called “ CKxxx”, please select the “ CKxxx”. 5. A window will prompt out for showing a pairing code , please type exactly the provided code on the keyboard as shown in the window and then press the “Enter” on the keyboard to confirm the pairing. 6. After the Step 5, indicator LED will stop flashing, the keyboard should be able to show up in the “Mouse, keyboard, & pen” category, now the keyboard is connected to the target PC and ready to use. Special function keys on CK series Keyboard For all versions Fn + = RF Pair Fn + WIN = App Fn + F10 = Print screen Fn + F11 = Scroll Lock Fn + F12 = Pause Fn + Delete = Insert Fn + Up arrow = Page up Fn + Down arrow = Page down Fn + Left arrow = Home Fn + Right arrow = End Only for backlit versions Fn + = BT1 Pair Fn + = BT2 Pair Fn + = BT3 Pair Fn + = USB connection Fn + F8 = Decrease Backlit Brightness ; Fn + F9 = Increase Backlit Brightness (For Wireless version, backlit will turn off to save power if there is no key stroke detected within 10 secs ) Cleaning the Keyboard (CK Series Only) 1. Fn + Right Shift = Disabling the typing function for keyboard cleaning, press Fn + Right Shift again to unlock 2. Spray/Wipe with medical -grade cleaner Charging the Keyboard Connect the keyboard to a USB2.0 port rated at 500mA , the keyboard will start charging immediately, 5 hours is recommended for fully charging the Keyboard. This device complies with part 15 of the FCC Rules. Operation is subject to the following two conditions: (1) this device may not cause harmful interference, and (2) this device must accept any interference received, including interference that may cause undesired operation. Any changes or modifications not expressly approved by the party responsible for compliance could void the user's authority to operate the equipment. NOTE: This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant to Part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference in a residential installation. This equipment generates, uses and can radiate radio frequency energy and, if not installed and used in accordance with the instructions, may cause harmful interference to radio communications. However, there is no guarantee that interference will not occur in a particular installation. If this equipment does cause harmful interference to radio or television reception, which can be determined by turning the equipment off and on, the user is encouraged to try to correct the interference by one or more of the following measures: -- Reorient or relocate the receiving antenna. -- Increase the separation between the equipment and receiver. -- Connect the equipment into an outlet on a circuit different from that to which the receiver is connected. -- Consult the dealer or an experienced radio/TV technician for help. The device has been evaluated to meet general RF exposure requirement. The device can be u sed in portable exposure condition without restriction

(Heng Yu Electronic Manufacturing Co. Ltd.) (July 11, 2023) Eurofins Electrical and Electronic Testing NA, Inc. 914 West Patapsco Avenue Baltimore, MD 21230 RE: Attestation Statements Part 2.911(d)(5)(i) request for (FCC ID: XEN-CK78) [Heng Yu Electronic Manufacturing 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. Sincerely, (Applicant signature) (Applicant printed name) H.K. Chan (Heng Yu Electronic Manufacturing Co. Ltd.) (July 11, 2023) Eurofins Electrical and Electronic Testing NA, Inc. 914 West Patapsco Avenue Baltimore, MD 21230 RE: Attestation Statements Part 2.911(d)(5)(ii) request for (FCC ID: XEN-CK78) [Heng Yu Electronic Manufacturing 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 an entity producing “covered” equipment. Sincerely, (Applicant signature) (Applicant printed name) H.K. Chan

Heng Yu Electronic Manufacturing Co. Ltd. Model Difference Data：2023.07.11 Product description: CK78 Model name: CK78, C78, CKW78A Trade Name: N/A FCC ID: XEN-CK78 All the model are the same circuit and RF module, except model names. Regards Sincerely Client’s signature : Client’s name / title : H.K. Chan (R&D Manager) Contact information / address: Room 1503-5, Nan Fung Commercial Centre, 19 Lam Lo Hong Kong, China

Heng Yu Electronic Manufacturing Co. Ltd. (July 11, 2023) Eurofins Electrical and Electronic Testing NA, Inc. 914 West Patapsco Avenue Baltimore, MD 21230 RE: CONFIDENTIALITY REQUEST FOR CK78 / CK78, C78, CKW78A / FCC ID: XEN-CK78 ) To Whom It May Concern: This letter serves as an official request for confidentiality under sections 0.457 and 0.459 of CFR 47. We have requested that the Exhibits Long-Term Confidentiality Short-Term Confidentiality NOTE 2 ID Label/Location No No Attestation Statement No No External Photos No ☐ Block Diagram ☒ ☐ Schematics ☒ ☐ Test Report No No Test Setup Photos No ☐ User’s Manual ☐ NOTE 1 ☒ Internal Photos ☐ NOTE 1 ☒ Parts List / Tune Up ☐ ☐ RF Exposure Info No No Operational Description ☒ ☐ Cover Letter(s) No No SDR Software / Security Info ☐ No required to be submitted with this application be permanently withheld from public review. Above mentioned document contains detailed system and equipment description are considered as proprietary information in operation of the equipment. The public disclosure of above documents might be harmful to our company and would give competitor an unfair advantage in the market. Please contact me if there is any information you may need. Sincerely, Signature: Name: H.K. Chan Title: R&D Manager

Heng Yu Electronic Manufacturing Co. Ltd. (July 11, 2023) Eurofins Electrical and Electronic Testing NA, Inc. 914 West Patapsco Avenue Baltimore, MD 21230 RE: LETTER OF AGENT AUTHORIZATION To Whom It May Concern: We, the undersigned, hereby authorize (Shenzhen CTB Testing Technology Co., Ltd.) to act on our behalf in all matters relating to application for equipment authorization, including the signing of all documents relating to these matters. We also hereby certify that no party to the application authorized hereunder is subject to the denial of benefits, including FCC benefits, pursuant to Section 5301 of the Anti-Drug Abuse Act of 1988, 21 U.S.C.853(a). This agreement expires one year from the current date. Sincerely, Signature: Name: H.K. Chan Title: R&D Manager

External Photos

FCC ID LABEL: Label Location: FCC ID: XEN-CK78 Model No.: CK78

Internal Photos ANT

Shenzhen CTB Testing Co., Ltd. FCC ID:XEN-CK78 Portable device According to §15.247(e)(i) and §1.1307(b)(1), systems operating under the provisions of this section shall be operated in a manner that ensures that the public is not exposed to radio frequency energy level in excess of the Commission’s guidelines. According to KDB447498 D01 General RF Exposure Guidance V06 The 1-g SAR and 10-g SAR test exclusion thresholds for 100 MHz to 6 GHz at test separation distances ≤ 50 mm are determined by: [(max. power of channel, including tune-up tolerance, mW)/(min. test separation distance, mm)]·[√f(GHZ)] ≤ 3.0 for 1-g SAR and ≤ 7.5 for 10-g extremity SAR, where: • f(GHZ) is the RF channel transmit frequency in GHz • Power and distance are rounded to the nearest mW and mm before calculation • The result is rounded to one decimal place for comparison When the minimum test separation distance is < 5 mm, a distance of 5 mm is applied to determine SAR test exclusion. BLE: Modulation Channel Freq. (GHz) Conduct ed power (dBm) Conducte d power (mW) Tune-up power (dBm) Max tune-up power (dBm) Max tune-up power (mW) Distance (mm) Result calculatio n SAR Exclusion threshold SAR test exclusion 2.402 -1.684 0.68 -1±1 0.00 1.00 <5 0.30997 3.00 YES 2.44 -1.319 0.74 -1±1 0.00 1.00 <5 0.31241 3.00 YES 2.480 -2.43 0.57 -2±1 -1.00 0.79 <5 0.25018 3.00 YES GFSK Conclusion: For the max result : 0.31241≤ FCC Limit 3.0 for 1g SAR.

PCB Antenna for BLE Chips of WCH 1、Dimension of Antenna 2、Features  Dimension: 5.6*12.3mm  Terminal impedance: 50 ohm  Max Gain: 2.1dBi  RF Frequency: 2.4GHz 3、S parameter Working bandwidth: 157MHz S11：[email protected] 4、Gain and Radiation pattern Max gain @2.4GHz: 2.08dBi E plane： H plane： Max Gain @2.44GHz: 2.1dBi E plane： H plane： Max Gain @2.48GHz: 2.04dBi E plane： H plane：

Shenzhen CTB Testing Technology Co., Ltd. Report No.: CTB230706044RFX Report Tel: 4008-707-283 Web: http://www.ctb-lab.net Page 1 of 35 TEST REPORT Compiled by: Reviewed by: Approved by: Chen Zheng Arron Liu Bin Mei / Director Note: If there is any objection to the inspection results in this report, please submit a written report to the company within 15 days from the date of receiving the report. The test report is effective only with both signature and specialized stamp. This result(s) shown in this report refer only to the sample(s) tested. Without written approval of Shenzhen CTB Testing Technology Co., Ltd. this report can’t be reproduced except in full. The tested sample(s) and the sample information are provided by the client. “*” indicates the testing items were fulfilled by subcontracted lab. “#” indicates the items are not in CNAS accreditation scope. Product Name: CK78 FCC ID: XEN-CK78 Trademark: N/A Model Number: CK78, C78, CKW78A Prepared For: Heng Yu Electronic Manufacturing Co. Ltd. Address: Room 1503-5, Nan Fung Commercial Centre, 19 Lam Lo Hong Kong, China Manufacturer: Zhuhai Heng Yu New Technology Company Limited Address: 1/F, Hengke Campus, Yunong Village North, Sanzao Town, Zhuhai, Guangdong, China Prepared By: Shenzhen CTB Testing Technology Co., Ltd. Address: 1&2/F., Building A, No.26, Xinhe Road, Xinqiao, Xinqiao Street, Bao'an District, Shenzhen, Guangdong, China Sample Received Date: Jun. 28, 2023 Sample tested Date: Jun. 28, 2023 to Jul. 07, 2023 Issue Date: Jul. 07, 2023 Report No.: CTB230706044RFX Test Standards FCC Part15.247 ANSI C63.10:2013 Test Results PASS Remark: This is Bluetooth radio test report. Shenzhen CTB Testing Technology Co., Ltd. Report No.: CTB230706044RFX Report Tel: 4008-707-283 Web: http://www.ctb-lab.net Page 2 of 35 TABLE OF CONTENT Test Report Declaration Page 1. VERSION ........................................................................................................................................ 3 2. TEST SUMMARY ........................................................................................................................... 4 3. MEASUREMENT UNCERTAINTY ................................................................................................. 5 4. PRODUCT INFORMATION AND TEST SETUP ............................................................................ 6 4.1 Product Information .......................................................................................................................... 6 4.2 Test Setup Configuration .................................................................................................................. 6 4.3 Support Equipment........................................................................................................................... 6 4.4 Channel List ..................................................................................................................................... 7 4.5 Test Mode ........................................................................................................................................ 7 4.6 Test Environment ............................................................................................................................. 7 5. TEST FACILITY AND TEST INSTRUMENT USED ....................................................................... 8 5.1 Test Facility ...................................................................................................................................... 8 5.2 Test Instrument Used ....................................................................................................................... 8 6. AC POWER LINE CONDUCTED EMISSION ................................................................................ 10 6.1 Block Diagram Of Test Setup ......................................................................................................... 10 6.2 Limit ................................................................................................................................................ 10 6.3 Test procedure ............................................................................................................................... 10 6.4 Test Result ..................................................................................................................................... 12 7. RADIATED SPUR IOUS EMISSION ............................................................................................. 14 7.1 Block Diagram Of Test Setup ......................................................................................................... 14 7.2 Limit ................................................................................................................................................ 14 7.3 Test procedure ............................................................................................................................... 15 7.4 Test Result ..................................................................................................................................... 16 8. BAND EDGE AND RF COUNDUCTED SPURIOUS EMISSIONS ............................................... 23 8.1 Block Diagram Of Test Setup ......................................................................................................... 23 8.2 Limit ................................................................................................................................................ 23 8.3 Test procedure ............................................................................................................................... 23 8.4 Test Result ..................................................................................................................................... 24 9. COUDUCTED OUTPUT POWER ................................................................................................. 26 9.1 Block Diagram Of Te…

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Radiated Emission Below 1G Above 1G Conducted emissions