HF-LPT200 Low Power WiFi Module User Manual HF-LPT200 Low Power WiFi Module User Manual Overview of Characteristic yi ng V 1.2 Support IEEE802.
HF-LPT200 Low Power WiFi Module User Manual TABLE OF CONTENTS LIST OF FIGURES ...................................................................................................................................6 LIST OF TABLES ....................................................................................................................................7 HISTORY ...............................................................................................................................................
HF-LPT200 Low Power WiFi Module User Manual 3.2.4. 3.3. Typical Application Examples ..............................................................................................27 3.3.1. Wireless Control Application .............................................................................................27 3.3.2. Remote Management Application.....................................................................................28 3.3.3. Transparent Serial Port Application ........................
HF-LPT200 Low Power WiFi Module User Manual AT+SNDB ..................................................................................................................43 4.2.2.35. AT+RCVB ..................................................................................................................43 4.2.2.36. AT+WSSSID ..............................................................................................................43 4.2.2.37. AT+WSKEY ..................................................
HF-LPT200 Low Power WiFi Module User Manual APPENDIX B: HTTP PROTOCOL TRANSFER ..............................................................................58 B.1. HTTP AT command ...................................................................................................................58 B.1.1. AT+HTTPURL ...................................................................................................................58 B.1.2. AT+HTTPTP .........................................................
HF-LPT200 Low Power WiFi Module User Manual LIST OF FIGURES HF-LPT200 View ..................................................................................................................11 Figure 2. HF-LPT200 Pins Map ...........................................................................................................11 Figure 3. HF-LPT200 Mechanical Dimension......................................................................................13 Figure 4. HF-LPT200 PCB Symbol Size .........
HF-LPT200 Low Power WiFi Module User Manual LIST OF TABLES HF-LPT200 Module Technical Specifications .......................................................................10 Table 2 HF-LPT200 Pins Definition ....................................................................................................11 Table 3 HF-LPT200 External Antenna Parameters ...........................................................................14 Table 4 HF-LPT200 Evaluation Kit Interface Description ..............
HF-LPT200 Low Power WiFi Module User Manual HISTORY Ed. V1.0 12-20-2013 First Version. Ed. V1.0.1 12-25-2013. Update product view. Ed. V1.1 01-02-2014. Update AT command, add AT+SMTLK、AT+LPTIO. Ed. V1.2 03-13-2014. Update product view and package. Update AT+TCPDISB, AT+NETP, H ig h- Fl yi ng AT+FCLR.description. Shanghai High-Flying Electronics Technology Co., Ltd(www.hi-flying.
HF-LPT200 Low Power WiFi Module User Manual 1. PRODUCT OVERVIEW 1.1. General Description The HF-LPT200 is a fully self-contained small form-factor, single stream, 802.11b/g/n Wi-Fi module, which provide a wireless interface to any equipment with a Serial/SPI interface for data transfer.
HF-LPT200 Low Power WiFi Module User Manual 1.1.2 Device Paremeters Table 1 Parameters Certification Wireless standard Frequency range FCC/CE 802.11 b/g/n 2.412GHz-2.484GHz 802.11b: +16 +/-2dBm (@11Mbps) 802.11g: +14 +/-2dBm (@54Mbps) 802.11n: +13 +/-2dBm (@HT20, MCS7) 802.11b: -93 dBm (@11Mbps ,CCK) 802.11g: -85 dBm (@54Mbps, OFDM) 802.11n: -82 dBm (@HT20, MCS7) External: Pad interface Internal:On-board Chip antenna UART SPI, GPIO 2.8~3.
HF-LPT200 Low Power WiFi Module User Manual 1.2. Hardware Introduction Pins Definition H ig h- Fl yi 1.2.1. HF-LPT200 View ng Figure 1. Figure 2. Table 2 HF-LPT200 Pins Map HF-LPT200 Pins Definition Pin Describtion Net Name SPI_MOSI Signal Type O 1 SPI Data Out 2 GPIO1, No connect if not use. SPI Interface SPI_CLK I/O GPIO2, No connect if not use.
HF-LPT200 Low Power WiFi Module User Manual Describtion Net Name 13 Wi-Fi Status nLink Signal Type O 14 GPIO14 GPIO14 I/O 15 +3.3V Power DVDD Power 16 Ground GND Power Ant_2.4G O 17 2.4GHz Antenna PAD nReload Pin (Button) function： 1. Comments “0” – Wi-Fi connect to router “1” – Wi-Fi unconncted; Detailed functions see Can be used for sleep control or WPS function Power Input: 2.6~3.
HF-LPT200 Low Power WiFi Module User Manual Power Supply & Power Consumption: Parameter Condition Operating Supply voltage Min. Typ. Max. Unit 2.8 3.3 3.8 V Supply current, peak Continuous Tx 200 mA Supply current, IEEE PS DTIM=100ms 12 mA Output high voltage Sourcing 6mA Output low voltage Sinking 6mA 2.8 Input high voltage 2.2 Input low voltage V V 0.8 V Mechanical Size ng 1.2.3. V 0.2 H ig h- Fl yi HF-LPT200 modules physical size （Unit: mm） as follows: Figure 3.
HF-LPT200 Low Power WiFi Module User Manual 1.2.4. On-board Chip Antenna HF-LPT200 module support internal on-board chip antenna option. When customer select internal antenna, you shall comply with following antenna design rules and module location suggestions: For customer PCB, RED color region (8.3x18.
Figure 6. yi ng HF-LPT200 Low Power WiFi Module User Manual HF-LPT200 Evaluation Kit Notes: User need download USB to UART port driver from High-Flying web or contact with technical Fl support people for more detail. The external interface description for evaluation kit as follows: HF-LPT200 Evaluation Kit Interface Description H ig h- Table 4 Function External Interface Name Description RS232 Main data/command RS-232 interface USB UART to USB debug interface.
HF-LPT200 Low Power WiFi Module User Manual 1.2.7. Order Information Base on customer detailed requirement, HF-LPT200 series modules provide different variants and Figure 7. HF-LPT200 Order InformationTypical Application Hardware Typical Application H ig h- Fl yi 1.2.8. ng physical type for detailed application. Figure 8. HF-LPT200 Hardware Typical Application Notes: nReset- Module hardware reset signal. Input. Logics “0” effective.
HF-LPT200 Low Power WiFi Module User Manual (This pin is recommend to connect to LED, indicate status when the module in wireless upgrade mode) When module connects to AP (AP associated), this pin will output “0”. This signal used to judge if module already at WiFi connection status. Thers is pull-up resister internal and no external pull-up required. If nLink function not required, can leave this pin open. nReady- Module boot up ready signal. Output. Logics “0” effective.
HF-LPT200 Low Power WiFi Module User Manual 2. FUNCTIONAL DESCRIPTION 2.1. Wireless Networking HF-LPT200 module can be configured as both wireless STA and AP base on network type. Logically there are two interfaces in HF-LPT200. One is for STA, and another is for AP. When HF-LPT200 works as AP, other STA equipments are able to connect to HF-LPT200 module directly. Wireless Notes: ng Networking with HF-LPT200 is very flexible.
yi ng HF-LPT200 Low Power WiFi Module User Manual Figure 10. HF-LPT200 AP+STA Network Structure Fl When module enables AP+STA function, Module’s STA interface can connect with router and connect to TCP server in the network.
HF-LPT200 Low Power WiFi Module User Manual Wireless Network Name（SSID） Security Mode Encryption Key TCP/UDP Linking Parameters Protocol Type Link Type（Server or Client） Target Port ID Number Target Port IP Address Serial Port Parameters Baud Rate Data Bit Parity (Check) Bit Stop Bit Hardware Flow Control 2.3. UART Frame Scheme 2.3.1. UART Free-Frame ng Wireless Network Parameters yi Fl HF-LPT200 support UART free-frame function.
HF-LPT200 Low Power WiFi Module User Manual Detailed UART auto-frame function can refer to AT+instruction set “UARTF/UARTFT/UARTFL” introduction. 2.4. Encryption Encryption is a method of scrambling a message that makes it unreadable to unwanted parties, adding a degree of secure communications. There are different protocols for providing encryption, and WEP WPA-PSK/TKIP WPA-PSK/AES WPA2-PSK/TKIP WPA2-PSK/AES ng the HF-LPT200 module supports following: 2.5.
HF-LPT200 Low Power WiFi Module User Manual General “config.txt” file format as following example: [URL]=http://10.10.100.100:80/lpb.bin [URL]= the URL address of Application. Direct Download and Upgrade AT+UPURL command to set the remote directory and file name, such as: AT+UPURL=http://www.hi-flying.com/!admin/down/,lpb.bin After excuate this command, the module will directly download the “lpb.bin” file from remote directory ng and start upgrade Application.
HF-LPT200 Low Power WiFi Module User Manual Downstream: All data from serial port (user) will be duplicate and broadcast to every TCP connection or client. ng Detailed multi-TCP link data transmition structure as following figure: H ig h- Fl yi Figure 12. Multi-TCP Link Data Transmition Structure Shanghai High-Flying Electronics Technology Co., Ltd(www.hi-flying.
HF-LPT200 Low Power WiFi Module User Manual 3. OPERATION GUIDELINE 3.1. Configuration via Web Accessing When first use HF-LPT200 modules, user may need some configuration. User can connect to HFLPT200 module’s wireless interface with following default setting information and configure the module through laptop. HF-LPT200 Web Access Default Setting Default Setting HF-LPB100 IP Address 10.10.100.254 Subnet Mask 255.255.255.
HF-LPT200 Low Power WiFi Module User Manual 3.1.2. Upgrade Software Page yi ng User can upgrade new software (firmware) version through Wi-Fi. Figure 14. Upgrade SW page 3.2.1. Software Debug Tools Fl 3.2. HF-LPT200 Usage Introduction High-Flying use two common software tools debugging and applying HF-LPT200 module. H ig h- (User can also select other tools used to debug serial port). 3.2.2.
HF-LPT200 Low Power WiFi Module User Manual connection, another PC1 (or user device) connect to HF-LPT200 module with serial port. Figure 16. AP Interface Debug Connection 3.2.4. Default Parameter Setting Default SSID: HF-LPB100; Deault security mode: open,none; User UART parameter setting:115200,8,1,None; Default network parameter setting:TCP,Server,8899,10.10.100.254; Module IP address: dhcp,0.0.0.0,0.0.0.0,0.0.0.0; Module Debug ng 3.2.3.
HF-LPT200 Low Power WiFi Module User Manual Figure 19. ng Then setting the TCP/UDP connection parameters. Default as following: “TCPUDPDbg” Tools Setting H ig h- Fl yi Then, click “Create” button to create a connection. Figure 20. “TCPUDPDbg” Tools Connection Now, in transparent transmission mode, data can be transferred from “CommTools” program to “TCPUDPDbg” program, or in reverse. You can see data in receiver side will keep same as in sender side. 3.3. Typical Application Examples 3.3.1.
HF-LPT200 Low Power WiFi Module User Manual For this wireless control application, HF-LPT200 works as AP mode. Module’s serial port connects to user device. So, control agent (Smart phone for this example) can manage and control the user device through the wireless connection with HF-LPT200 module. Remote Management Application ng 3.3.2. yi Figure 22. Remote Management Application For this remote management application, HF-LPT200 works as STA mode and connects to Internet through wireless AP.
HF-LPT200 Low Power WiFi Module User Manual 4. AT+INSTRUCTION INTRODUCTION 4.1. Configuration Mode When HF-LPT200 power up, it will default works as transparent transmission mode, then user can switch to configuration mode by serial port command. HF-LPT200 UART default parameters setting as yi ng below figure, Figure 24. HF-LPT200 Default UART Port Parameters page setting function. 4.1.1.
HF-LPT200 Low Power WiFi Module User Manual 2. Any other input or wrong step to UART port will cause the module still works as original mode (transparent transmission). 3. “+++” and “a” should be input in a certain period of time to make the module switch to configuration ng mode. Like the following sequence. 4.2. AT+Instruction Set Overview User can input AT+Instruction through hyper terminal or other serial debug terminal, also can program the AT+Instruction to script.
HF-LPT200 Low Power WiFi Module User Manual AT+[op][para-1,para-2,para-3,para-4…] AT+: CMD: Command string; [op]: Prefix of command message; Symbol of command operator, “=” : The command requires parameters input; “NULL”: Query the current command parameters setting; [para-n]: Parameters input for setting if required; :”Enter” Key, it’s 0x0a or 0x0d in ASCII; ng Notes: When input AT+Instruction, “AT+” character will display capital letter automatic and other
HF-LPT200 Low Power WiFi Module User Manual H ig h- Fl yi ng Instruction Description MID Query module ID information VER Query module software version information LVER Query module detailed software version FWSZ Query Wi-Fi driver size RELD Restore to factory default setting FCLR Erase factory setting Z Re-start module H Help Configure Parameters Instruction Set CFGRD Batch Read User Configure Parameters CFGWR Batch Write Configure Parameters CFGFR Batch Read Factory Default Configure Parameters CFGTF
HF-LPT200 Low Power WiFi Module User Manual H ig h- Fl yi ng Instruction Description WADHCP Set/Query AP DHCP Server status WADMN Set/Query AP webpage domain name WALK Query MAC address of STA device connecting to module AP WALKIND Enable/Disable indication of connection status.
HF-LPT200 Low Power WiFi Module User Manual Format: Query Operation AT+WMODE +ok= Set Operation AT+WMODE= +ok Parameters: mode:Wi-Fi work mode AP STA APSTA ng 4.2.2.3. AT+ENTM Function: Set module into transparent transmition mode; Format: +ok yi AT+ENTM When operate this command, module switch from configuration mode to transparent transmission Fl mode. 4.2.2.4.
HF-LPT200 Low Power WiFi Module User Manual HF-LPB100; Notes: User can set this parameter through AT+WRMID. 4.2.2.6. AT+VER Function: Query module software version information; Format: Query Operation AT+VER +ok= Parameters: ver: Module software version information; ng 4.2.2.7.
HF-LPT200 Low Power WiFi Module User Manual 4.2.2.11. AT+Z Function: Re-start module; Format: AT+Z 4.2.2.12. AT+H Function: Help; Format: Query Operation AT+H Parameters: command help: command introduction; 4.2.2.13.
HF-LPT200 Low Power WiFi Module User Manual Query Operation AT+CFGTF +ok= Parameters: status: feedback operation status; 4.2.2.17. AT+UART Function: Set/Query serial port parameters. Setting is valid after reset.
HF-LPT200 Low Power WiFi Module User Manual 4.2.2.19. AT+UARTFT Function: Set/Query UART auto-frame trigger time; Format: Query Operation AT+UARTFT +ok=
HF-LPT200 Low Power WiFi Module User Manual data_lenth: Lenth of send data. Range: 0~1000 Byte The UART port will wait 3 seconds for input after this command is sent OK. The data received from UART port is sent to SOCKA. If the interval of two bytes is more than 10ms, the data will be sent instantly. 4.2.2.23. AT+RECV Function: Receive Data from SOCKA at Command Mode.
HF-LPT200 Low Power WiFi Module User Manual IP: Server’s IP address or domain name when module set as client If set as UDP SERVER, the module will save the IP address and port of the latest UDP packet received. The data will be sent to the saved IP address and port. If the module hasn’t saved any IP address and port when power up. The data will be sent to the IP address and port which is set by this command.
HF-LPT200 Low Power WiFi Module User Manual Default, 300s; Module begin to count time when TCP channel don’t receive any data, clecherar time counter when TCP channel receive any data. If the time counter reaches the TCPTO, the tcp channel will be break. If the module work in TCP Client, it will connect the TCP server instantly and when the module work in TCP Server, the TCP client device should make the connection itself. 4.2.2.29.
HF-LPT200 Low Power WiFi Module User Manual If set as UDP,CLIENT, the data will always be sent to the IP address and port set by this command. 4.2.2.31. AT+TCPDISB Function: Open/Close SOCKB connection Format: Query Operation AT+TCPDISB +ok= Set Operation ng AT+TCPDISB = +ok Parameters: When setting, “off” means close TCP link. After finish this command, module disconnect TCP link and not connect again. “On” means open TCP link.
HF-LPT200 Low Power WiFi Module User Manual 4.2.2.34. AT+SNDB Function: Send datas to SOCKB at Command Mode Format: AT+SNDB= +ok Parameters: data_lenth: Lenth of send data. Range: 0~1000 Byte The UART port will wait 3 seconds for input after this command is sent OK. The data received from UART port is sent to SOCKB. If the interval of two bytes is more than 10ms, the data will be ng sent instantly. 4.2.2.35.
HF-LPT200 Low Power WiFi Module User Manual OPEN SHARED WPAPSK WPA2PSK encry:Encryption algorithm NONE: When “auth=OPEN”, effective WEP: When “auth=OPEN” or “SHARED”, effective TKIP: When ”auth= WPAPSK” or “WPA2PSK”, effective AES: When “auth= WPAPSK” “WPA2PSK”, effective key: password, ASCII code, shall less than 64 bit and greater than 8bit ng 4.2.2.38. AT+WANN Function: Set/Query STA network setting. Setting is valid after reset.
HF-LPT200 Low Power WiFi Module User Manual Format: Query Operation AT+WSLK +ok= Parameters: ret ”Disconnected”, if no WiFi connection; ”AP’ SSID（AP’s MAC” ）, if WiFi connection available; Function: Query STA WiFi signal strength; Format: Query Operation AT+WSLQ +ok= Parameters: ret yi ng 4.2.2.41.
HF-LPT200 Low Power WiFi Module User Manual +ok= Set Operation AT+LANN=< ipaddress,mask> +ok Parameters: ipaddress: AP’s IP address; mask: AP’s net mask; 4.2.2.45. AT+WAP Function: Set/Query AP Wi-Fi parameters. Setting is valid after reset.
HF-LPT200 Low Power WiFi Module User Manual 4.2.2.47. AT+WAMAC Function: Query AP MAC address parameters; Format: Query Operation AT+WAMAC +ok= Parameters: mac_address:AP’s MAC address; Note: Module AP mode’s MAC address is related to STA mode’s MAC address. If user need 4.2.2.48. AT+WADHCP ng changeto others, please contact with high-flying technical people. Function: Set/Query AP DHCP server status; Setting is valid after reset.
HF-LPT200 Low Power WiFi Module User Manual status: MAC address of STA device connecting to module AP. No Connection: No STA device connecting to module AP; 4.2.2.51. AT+WALKIND Function: Enable/Disable indication of module AP connection status. Format: Query Operation AT+WALKIND +ok= Set Operation ng AT+WALKIND= +ok Parameters: status: indication of module AP connection status. on: Enable nLink indication function.
HF-LPT200 Low Power WiFi Module User Manual filename: the upgrade file name, it’s optional and not saved parameter. If provide this file name here, the module will start upgrade right away; 4.2.2.54. AT+UPFILE Function: Set/ Query remote upgrade configure file name; Format: Query Operation AT+UPFILE +ok= Set Operation ng AT+UPFILE= +ok Parameters: filename: the upgrade configure file name (within 20 characters). 4.2.2.
HF-LPT200 Low Power WiFi Module User Manual Query Operation AT+UPST +ok= Parameters: log: feedback the status of remote upgrade; Note: After execute this command, the HF-LPB100 will automatic start upgrade base on the setting of UPURL, UPFILE command contents; 4.2.2.58. AT+WEBU Function: Set/ Query webpage user name and password; Setting is valid after reset.
HF-LPT200 Low Power WiFi Module User Manual +ok Parameters: num：time calibration inverval，range:0~720, default:30 minutes, 10 minutes for each step, set 0 means no time calibration automatically. 4.2.2.61. AT+NTPEN Function: Enable/Disable time calibration function. Setting is valid after reset.
HF-LPT200 Low Power WiFi Module User Manual AT+RLDEN= +ok Parameters: status: The status of module’s nReload pin function on: nReload pin function is enabled. off: nReload pin function is disabled 4.2.2.65. AT+ASWD Function: Set/Query WiFi Configuration Password; Format: Query Operation AT+ASWD +ok= Set Operation AT+ASWD= Parameters: aswd: WiFi Configuration Password (within 20 characters).
HF-LPT200 Low Power WiFi Module User Manual AT+TXPWR= +ok Parameters: num: [Setting Value]. The default is 0, it can be sent from 0 ~ 24. If set to 24, the moudule transmit power will be at a minium of 4dBm. Reboot to make this setting change valid. It will not restore to default if reload the module. 4.2.2.68. AT+SMTLK Function: Start WPS function Format: Query Operation ng AT+SMTLK SmartLink is a One-Key config function.
HF-LPT200 Low Power WiFi Module User Manual 4.2.2.71. AT+LPTIO Function: nReady,nLink, WPS function mapping. Setting is valid after reset. Format: Query Operation AT+LPTIO +ok= Set Operation AT+ LPTIO = +ok Parameters: status: nReady,nLink, WPS function mapping. ng off/lpb100: nReady,nLink, WPS function are mapping to HF-LPB100 corresponding pin.
HF-LPT200 Low Power WiFi Module User Manual 5. PACKAGE INFORMATION ng 5.1. Recommended Reflow Profile yi Figure 27. Reflow Soldering Profile Table 11 Reflow Soldering Parameter Item Temperature (Degree) 1 Reflow Time 2 Peak-Temp Time of above 220 Fl NO. Time(Sec) 35~55 sec 260 max Note: 1. Recommend to supply N2 for reflow oven. H ig h- 2. N2 atmosphere during reflow (O2<300ppm) 5.2. Device Handling Instruction (Module IC SMT Preparation) 1.
HF-LPT200 Low Power WiFi Module User Manual 5.3. Shipping Information TRAY BOX Size: 350*245*200 mm (inside) ng Size: 350*245*10 mm Figure 28. Shipping Information Note: 1 tray = 12*8pcs = 96pcs H ig h- Fl yi 1 box = 20 trays = 20 * 96 pcs = 1920pcs Shanghai High-Flying Electronics Technology Co., Ltd(www.hi-flying.
HF-LPT200 Low Power WiFi Module User Manual H ig h- Fl yi ng APPENDIX A: HW REFERENCE DESIGN Detailed HF-LPT200 Evluation Board design source files, pls access High-Flying web download page or contact with High-Flying technical support people to acquire. Shanghai High-Flying Electronics Technology Co., Ltd(www.hi-flying.
HF-LPT200 Low Power WiFi Module User Manual APPENDIX B: HTTP PROTOCOL TRANSFER HF-LPT200 module support http data transfer in command mode. If any detailed HTTP protocol, contact us and we may support customization. B.1. HTTP AT command AT+HTTPURL Function:Set /Query HTTP server IP address and Port Number. Format: Query Operation AT+HTTPURL +ok= Set Operation AT+HTTPURL= +ok Parameters: IP：IP address. Port：Port number.
HF-LPT200 Low Power WiFi Module User Manual B.1.4. Path：Max length is 50 bytes. AT+HTTPCN Function:Set/Query Connection of HTTP protocol header Format: Query Operation AT+HTTPCN +ok= Set Operation +ok Parameters: AT+HTTPUA Function:Set/Query User-Agent of HTTP protocol header. Format: Query Operation AT+HTTPUA yi B.1.5. Connection：Max length is 20 bytes.
HF-LPT200 Low Power WiFi Module User Manual If send “AT+HTTPDT”, the data packet will be sent as the following instance including the two new line: POST /abcd HTTP/1.1 Connection:keep-alive User-Agent:lwip1.3.2 Content-Length:0 Host:192.168.0.127:8999 If send AT+HTTPDT=abcd, the data packet will be sent as the following instance: ng POST /abcd HTTP/1.1 Connection:keep-alive User-Agent:lwip1.3.2 Content-Length:4 abcd yi Host:192.168.0.
HF-LPT200 Low Power WiFi Module User Manual APPENDIX C:REFERENCES C.1．High-Flying Mass Production Tool Download Address：http://www.hi-flying.com/download_detail_dc/&downloadsId=07bc0a59-0a0d- ng 4fb4-a5e5-c3403f09ab08&comp_stats=comp-FrontDownloads_list01-dc.html C.2．SmartLink APP Config Tool IOS Platform : http://www.hi-flying.com/download_detail_dc/&downloadsId=5cc0c241-77b4-48c1-bf9c- yi 2ad2954b3b50&comp_stats=comp-FrontDownloads_list01-dc.html Android Platform: http://www.hi-flying.
HF-LPT200 Low Power WiFi Module User Manual APPENDIX D: CONTACT INFORMATION ng -----------------------------------------------------------------------------------------------------------Address: Room.511/510, Building 7, No.365, Chuanhong Road, Pudong New Area, Shanghai, China, 201202 Web: www.hi-flying.com Service Online: 400-189-3108 Sales Contact: sales@hi-flying.
FCC STATEMENT 1. 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. (2) This device must accept any interference received, including interference that may cause undesired operation. 2. Changes or modifications not expressly approved by the party responsible for compliance could void the user's authority to operate the equipment.
