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Sim800L Net Light flashings

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Wp100

Well-Known Member
Hi,

Have one of these Sim800L Coreboards working fine and ordered another board recently.

However when the new board is powered up, the netlight flashes as if its searching, eg about once per second for 13 times, then pauses for 3 seconds then resumes for 13 flashes again etc.

I can talk to it with AT commands ok, but AT+CSQ, signal strength, shows 0,0 instead of 30,0

Cannot find any reference to this sequence of flashing , though not sure why it stops searching after 13 flashes ? the other board can take 20 flashes before it connects ok.

Does anyone know if these 13 flashes are a known message or just got a bad board ?

thanks


000416.jpg
 

Diver300

Well-Known Member
Most Helpful Member
It looks like it is trying to connect to a network, failing, turning off, and then turning back on and trying again.

The power supply needs to be able to meet the 2 A peak current, and a power supply issue can give the behaviour described.
 

Wp100

Well-Known Member
Thanks, but its on a 5A variable psu at 4.00v

Now seen some posts suggesting the problem may be in the AT+CBAND default settings, so just trying a variation on them.....


Edit,

Have compared the settings of the older working Sim800L with the new one and have got the CBAND as EGSM_MODE,ALL_BAND and the COPS shows "02" .

Have also tried changing to all of the different CBAND modes, this does affect the flashing, some settings a few flashes lower, other setting it flashes all the time, but seems it does not want to log on.

The Sim card is in the right way around , the 4v linear psu is good, the Arduino lines are correctly resistored exactly the same as the working old Sim800L, but something still not right ??
 
Last edited:

Wp100

Well-Known Member
Hi again,

My old Sim900 module and the Sim800L purchased last year both work fine on my Tesco(o2) Payg sim card, but on this new Sim800L, which looks identical to the older one, it does not work, as above.

Just tried a Virgin(EE) Sim card and the new 800L locks on to the network straight away !

The problem is no idea why, but can only assume some setting on the firmware for the 800L, plus need to use a Sim card like the Tesco one that allows a top up to be carried over for months when inactive, unlike most bundles which need monthly top up.

Any suggestion of what is stopping this new 800L from using the Tesco (o2) sim ?

thanks
 

fx4

New Member
Hi Wp100,
did you solve the issue with the flashing 'SIM800L EVB' without connection? I have the same problem: There is no connection to mobile network.

NET led is flashing about 10 times (searching for net), then NET led and Ring led are off for about 1 second (looks like reboot) and the again 10 time flashing NET led.

It seems, there is no connection.

This is what the SIM800L says:
> AT+COPS=?
Call Ready
SMS Ready
+COPS: (2,"E-Plus","E-Plus","26203"),(1,"D1","TMO D","26201"),(1,"vodafone","voda D2","26202"),,(0-4),(0-2)

> AT+COPS?
+COPS: 1
OK
RDY
+CFUN: 1
+CPIN: READY

> AT+CCID
8949xxxxxxxxxxxxxxxf
OK
+CPIN: READY

> AT+GSV
SIMCOM_Ltd
SIMCOM_SIM800L
Revision:1418B04SIM800L24
OK
+CPIN: READY

> AT+CSQ
+CSQ: 0,0
OK
+CPIN: READY

> AT+CBAND=?
+CBAND: (EGSM_MODE,DCS_MODE,GSM850_MODE,PCS_MODE,EGSM_DCS_MODE,GSM850_PCS_MODE,EGSM_PCS_MODE,ALL_BAND)
OK
+CPIN: READY

> AT+CSCLK?
+CSCLK: 0
OK
+CPIN: READY


Sim-card has no pin. Sim-card works fine with 3G- and old 2G mobile phone.

Has anyone an idea to connect this SIM800L to mobile network?

Thanks.
 

fx4

New Member
I could solve my problem by increasing supply voltage from 5V to 6.3V.

With 6.3V the Sim800l EVB can connect.
 

Nigel Goodwin

Super Moderator
Most Helpful Member
I suggest you check what's going on?, 6.3V is far above the maximum voltage - and (in my experience) the tiny SM800L modules give error messages for over and under voltage.
 
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