CODEWITHSUNDEEP
serial-portsmsgsmavrat-command
Mohammad Farahi
Mohammad Farahi

Reputation: 1066

AT+CMGS returns ERROR

I am using SIM900 GSM module connect to my AVR Microcontroller. I tested it with FT232 to see transmitting data. First Micro sends AT it will response OK

AT OK
AT+CMGF=1 OK
AT+CMGS="+9893XXXXXX" returns ERROR and doesn't show ">"

Could anybody advise me what to do?

Upvotes: 19

Views: 48932

Answers (5)

Вася Пупкин
Вася Пупкин

Reputation: 21

I have faced the same ERROR. All previous recommendations are right. I want just to share my experience. I use SIM800L module. It was tuned AT+CMGF=1 at start of my project. But as it turned out the sim-module forgot this parameter occasionally. The programm wasn`t able to send and read sms. And I was trying to find the reason of the problem for several days.

My recommendation is to check some parameters like CMGF=1, CSCS="GSM", CMEE=2 right before use the CMGS or CMGR commands.

Upvotes: 1

Temba
Temba

Reputation: 419

Sometimes the issue is the text mode you are in. Enter AT+CMGF? and you should receive +CMGF: 1. If instead you receive +CMGF: 0, enter AT+CMGF=1. This changes the message format from PDU mode to Text mode. I'm not sure what either of those mean exactly, but this fixed my issue.

SIM 800 AT command manual

Upvotes: 3

lav
lav

Reputation: 1481

If AT+CSCS? command returns UCS2, then many arguments need to be encoded as hex string of UTF-16 encoding, so the phone number would become "002B0039003800390033...", and the SMS text would need to be encoded in the same way. If you don't need UCS2 encoding, then the easiest thing to do is to switch to GSM encoding (or another encoding from the available set as shown by AT+CSCS=? command)

Upvotes: 3

yuriygorskyy
yuriygorskyy

Reputation: 336

Command AT+CSCS? will answer You what type of sms-encoding is used. Properly answer is "GSM", and if not, You should set it by command AT+CSCS="GSM".

And remember about "Ctrl+Z" (not "Enter") as a finish of sms text, please.

Upvotes: 22

Kobi K
Kobi K

Reputation: 7931

You aren't passing all the parameters to the command.

The command format is:

AT+CMGS=<number><CR><message><CTRL-Z>

Where:

<CR> = ASCII character 13
<CTRL-Z> = ASCII character 26

You have passed only the number and without the <CR> you won't see the > note for the message.

Example:

AT+CMGS="+9893XXXXXX"
> This is the message.→

The response is:

+CMGS:<mr>
OK

Where <mr> is the message reference.

Upvotes: 6

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