SIM800L SMS Doubt

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Suraj143

Active Member

• Apr 2, 2019

• #1

I'm doing a project using SIM800L module.
I can send a SMS using this command. AT+CMGS="Phone Number"....

My question is, after I sent the SMS do I need to clear the SMS buffer?Not sure this module has a sent buffer...!!!

Or

Need to clear only when I receive a SMS (by reading Message storage command & delete them one by one)?

 

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Diver300

Well-Known Member

Most Helpful Member

• Apr 7, 2019

• #2

I've not used the SIM800L module, but sending SMSs with the Telit module doesn't need anything clearing.

On the Telit modules they store incoming messages on the SIM so they have to be cleared or the SIM gets full.

 

Nigel Goodwin

Super Moderator

Most Helpful Member

• Apr 7, 2019

• #3

I've never found one yet where you have to clear anything after sending, why not just try it and see?

 

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Suraj143

Active Member

• Apr 18, 2019

• #4

Ok thanks.

I have another small issue.My SIM800L module when it is in lower GSM signal areas it will disconnect, but it never reconnect automatically.

Is there anyway to reconnect to the network automatically?Any AT commands to be set? Or do I need to read modules signal strength all the time?

 

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Diver300

Well-Known Member

Most Helpful Member

• Apr 18, 2019

• #5

This could be a power supply issue. In lower signal areas the module will use more power and a poor power supply may upset it.

On other GSM modules, I have found that there are conditions where they won’t connect until turned off and back on.

 

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Suraj143

Active Member

• Apr 18, 2019

• #6

Diver300 said:

This could be a power supply issue. In lower signal areas the module will use more power and a poor power supply may upset it.

On other GSM modules, I have found that there are conditions where they won’t connect until turned off and back on.

Click to expand...

You are correct.Power supply is giving more troubles in low signal areas.This time I added a proper power supply unit. Did not test the results yet.

Reading the signal level or network connectivity commands everytime is a big overhead ( because while reading this levels I could miss incoming calls or SMS messages).Like to get rid of doing this poling method.

 

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Diver300

Well-Known Member

Most Helpful Member

• Apr 18, 2019

• #7

I think that you are going to have to read information from the phone periodically whatever. I don't see why it would cause a call to be missed. There is a ring indicator line and you can suspend checking the network when that goes low.

 

Nigel Goodwin

Super Moderator

Most Helpful Member

• Apr 19, 2019

• #8

And text messages can be stored on the SIM card anyway, which is the default setting as well.