diff --git a/docs/en/module/nb-iot.md b/docs/en/module/nb-iot.md
index fa83da13..73719d69 100644
--- a/docs/en/module/nb-iot.md
+++ b/docs/en/module/nb-iot.md
@@ -76,6 +76,20 @@ Power Operation:
 <a href="https://m5stack.oss-cn-shenzhen.aliyuncs.com/EasyLoader/Module/EasyLoader_SIM800L_at.exe"><button type="button" class="btn btn-primary">Click to check the list: frequency band of Globle mobile operators </button></a>
 -->
 
+
+### Some national carrier frequency bands
+
+<table>
+ <tr><td>North America</td><td>B4 (1700), B12 (700), B66 (1700), B71 (600), B26 (850) </td></tr>
+ <tr><td>Asia Pacific</td><td>B1(2100), B3(1800), B5(850), B8(900), B18(850), B20(800), B26(850),B28(700)</td></tr>
+ <tr><td>Europe:</td><td> B3 (1800), B8 (900) , B20 (800) </td></tr>
+ <tr><td>Latin America</td><td>B2(1900), B3(1800), B5(850), B28(700) </td></tr>
+ <tr><td>Commonwealth of Independent States</td><td>BB3 (1800), B8 (900), B20 (800)</td></tr>
+ <tr><td>Sub-Saharan Africa</td><td>B3(1800), B8(900) </td></tr>
+ <tr><td>Middle East, North Africa</td><td>B8(900), B20(800)</td></tr>
+</table>
+
+
 ## Links
 
 -  **Datasheet** - [M5311 AT Command](http://iot.10086.cn/Uploads/file/product/20190216/M5311_AT_Command_Interface_Specification_v2_20190216181452_37713.pdf)
diff --git a/docs/zh_CN/module/nb-iot.md b/docs/zh_CN/module/nb-iot.md
index 8d4f9d63..b9b28e07 100644
--- a/docs/zh_CN/module/nb-iot.md
+++ b/docs/zh_CN/module/nb-iot.md
@@ -67,7 +67,28 @@
 -  智能停车
 -  市政管理
 
+### 部分国家运营商频段
 
+<table>
+ <tr><td>North America</td><td>B4 (1700), B12 (700), B66 (1700), B71 (600), B26 (850) </td></tr>
+ <tr><td>Asia Pacific</td><td>B1(2100), B3(1800), B5(850), B8(900), B18(850), B20(800), B26(850),B28(700)</td></tr>
+ <tr><td>Europe:</td><td> B3 (1800), B8 (900) , B20 (800) </td></tr>
+ <tr><td>Latin America</td><td>B2(1900), B3(1800), B5(850), B28(700) </td></tr>
+ <tr><td>Commonwealth of Independent States</td><td>BB3 (1800), B8 (900), B20 (800)</td></tr>
+ <tr><td>Sub-Saharan Africa</td><td>B3(1800), B8(900) </td></tr>
+ <tr><td>Middle East, North Africa</td><td>B8(900), B20(800)</td></tr>
+</table>
+
+
+
+<!-- North America: B4 (1700), B12 (700), B66 (1700), B71 (600), B26 (850) 
+Asia Pacific: B1(2100), B3(1800), B5(850), B8(900), B18(850), B20(800), B26(850)
+and B28(700); 
+Europe: B3 (1800), B8 (900) and B20 (800); 
+Latin America: B2(1900), B3(1800), B5(850) and B28(700) 
+Commonwealth of Independent States: B3 (1800), B8 (900) and B20 (800); 
+Sub-Saharan Africa: B3(1800) and B8(900); 
+Middle East and North Africa: B8(900) and B20(800);  -->
 
 ## 相关链接