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Last modified by Xiaoling on 2023/04/24 08:49
From version 10.2
edited by Xiaoling
on 2023/04/24 08:48
Change comment: There is no comment for this version
To version 5.4
edited by Xiaoling
on 2023/04/21 11:53
Change comment: There is no comment for this version

Summary

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1 -Signal Strength:99. CSQ:99,99
1 +CSQ:99,99
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1 -**Table of Contents:**
1 += **Introduction** =
2 2  
3 -{{toc/}}
4 -
5 -
6 -= 1. Issue Output =
7 -
8 8  ----
9 9  
10 -NB-IoT module can't connect to NB-IoT Network and Keep Showing Signal Strenght:99. Below is an example output:
5 +When you use NB-IoT module and run the command **AT+CSG=99,99**. It means the device doesn't attached to the NB-IoT network. If attached to network, the first 99 should be 2~~31.
11 11  
12 -[[image:image-20230423223628-1.png]]
13 -
14 -
15 -= 2. What is Signal Strenght? =
16 -
17 -Signal Strength is same as AT+CSQ command output. When you run (% style="color:blue" %)**AT+CSQ**(%%) and NB-IoT module return (% style="color:blue" %)**AT+CSQ=99,99**(%%). It means NB-IoT Sensor doesn't attached to the NB-IoT network. If attached to network, the first 99 should be 2~~31.
18 -
19 19  (((
20 20  Below is the definition for the (% style="color:blue" %)**AT+CSQ**
21 21  )))
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25 25  CSQ Definition
26 26  
27 27  
28 -= 3. What to check? =
29 29  
30 -== 3.1 Check whether module detect the SIM card? ==
17 +(% style="color:red" %)**In this case, you can check:**
31 31  
32 -You can see if the output shows the (% style="color:blue" %)**IMSI number**(%%). If NB-IoT module detects SIM card successful, There will be a IMSI number shown, this is from the SIM card. If SIM card not detect, please check:
19 +* Whether the antenna connection is good.
33 33  
34 -* If SIM card is placed in correct direction.
21 +* Whether you use a valid SIM Card
35 35  
36 -* Make sure there is power off / power on after insert SIM card.
23 +* Whether you the SIM card place correctly.
37 37  
38 -== 3.2 Whether you use a NB-IoT SIM card that the module supports ==
25 +* Whether the NB-IoT Network you use match the End Device Module support network.
39 39  
40 -* Make sure the SIM card you use is a (% style="color:blue" %)**NB-IoT SIM card**(%%). It is different from normal SIM card we use for mobile.
27 +* Whether you have select the correct band for your operator. See [[Specify_NB-IoT_Band>>doc:Main.Specify NB-IoT Band.WebHome]]
41 41  
42 -* If you use a NB-IoT SIM card, check whether the (% style="color:blue" %)**Frequency Band**(%%) of this operator are in the support list of the NB-IoT Sensor.
43 -
44 -== 3.3 Whether the antenna connection is good ==
45 -
46 - See  the connection of Antenna Path is loose.
47 -
48 - [[image:image-20230423230549-2.png||height="370" width="428"]]
49 -
50 -
51 -== 3.4 Check Software Settings ==
52 -
53 -In the NB-IoT Sensor which power by battery. The sensor will try to connect to NB-IoT in a specify time (For example 5 minutes), if sensor is not able to attach network in 5 minutes. Sensor will stop retry and put the NB-IoT module in sleep mode to save battery life. So in the case that attaching network needs more time than 5 minutes, it will cause module hard to attach NB-IoT network. There are two solution to solve this.
54 -
55 -=== 3.4.1 Extend attach time ===
56 -
57 -User can use AT Command to extend network acquisition time.For example (% style="color:blue" %)**AT+CSQTIME=10**(%%) will extend the network acquisition time to 10 minutes.
58 -
59 -
60 -=== 3.4.2 Lock Frequency Band ===
61 -
62 -NB-IoT module by default support multi-bands, and it will try to use these bands to attached network one by one. User can lock the frequency band to the SIM card band to speed up the process.
63 -
64 -See [[how to lock frequency band>>doc:Main.Specify NB-IoT Band.WebHome]].
65 -
66 66  
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