I have problems with the sim900. When I'm reading the serial port and the sim900 module receives a sms. It send an alert via serial port and cause problems with the reading.
I have tried using this command "AT+CNMI=0,0,0,0,0", it works fine if I really don't need sms, but I need them. what can i do if i don't want to receive new sms message notifications when I'm reading the serial port???
Thanks!
You may use AT+CNMI command to enable or disable New Message Indication messages on uart. Keep in mind that you wont get any notification for a message that is received when notifications are disabled so you need to implement a check for it.
You may either delete all existing messages using the AT+CMGD=1,4 command before disabling the notifications and check for all messages after after resuming notifications or implement any other check.
TO ENABLE NOTIFICATIONS "AT+CNMI=1,2,0,0,0"
TO DISABLE NOTIFICATIONS "AT+CNMI=0,0,0,0,0"
Related
At the moment I'm working with the Arduino and SIM900, well, I could say I'm intermediate with the SIM, I could accomplish sending data to my website and receiving data from another phone. But now I would need that when I press a toggle button on my website it will send a message to the SIM900, for example, If I check the button it will send 1 if uncheck it, it will send 0. The problem is, I don't know how to start, I already searched up how to send data to the SIM900, But what I always get is the SIM making a request to the server, I would need the server to send the message whenever it is pressed, without the need of the SIM to keep making requests. Will I need an API for this? Please Help
Your phone (client) is behind a NAT. To reach it, you should read about NAT Traversal tactics, which will enable you to push a message to a client.
You can achieve that with Socket.IO or MQTT.
Your server will have a piece of code that the client should connect to when it's up, and the server will maintain the connection alive so that the server can push messages over this connection.
I hit a deadened trying to receive sms on the SIM800L module with Arduino Uno.
I'm using the Receive sms sketch on the IDE, the module does not receive incoming messages and just keeps displaying one sms over and over, this message is the first one I sent to the module, and somehow it's stuck in memory. the sms.flush() method does't erase the message, how do I go about clearing memory to create space for incoming messages ? Thanks
The SIM800L has a vendor specific command to delete all messages, this may clear up enough space for it to receive additional messages.
Run AT+CMGDA=? to find out which mode you need to use. The modem responds with (1-6) or lists the responses in text mode.
Then run AT+CMGDA=6 if the modem responded with numbers, or AT+CMGDA="DEL ALL".
To avoid overflowing the storage, using AT+CNMI=2,2 you can tell the modem to always forward incoming messages to the terminal and avoid storing them in the SIM card or modem memory.
I am using QUECTEL M95 modem to connect the server using gprs . And the modem has facility to send and receive test messages .In my project both the situation occurs . By default in programming ip address been set, but there are chances for updating the ip address by sms . Wheather it is possible to send sms during gprs mode? If possible how ? Please suggest me how to do.
Yes, you can do it. If you are using Transparent mode (AT+QIMODE=1) you need to switch to Normal mode (AT+QIMODE=0) and you can send SMS using AT+CMGS regardless of active gprs connection.
You have to use the normal command mode (not to switch to transparent mode).
AT+QINDI=1 - to receive data with poll command
AT+QIRD - poll received data
AT+QISEND - send data
AT+CMGS - send SMS
AT+CMGL="REC UNREAD" - poll new messages
I would like to process sms messages from my GSM modem (SIM900, but have few others also) but without +CMTI notification.
Code would run in a look and execute various commands, and one of them would be to check if message arrived and then act upon that.
Currently if modem received sms it outpus +CMTI message which get somewhere in the buffer.
Would disabling of that be better approach or should I parse the structure?
Please run
AT+CNMI=0,0,0,0,0
This command silences all SMS URC notifications.
There are pro's and con's with both ways of dealing with receiving and handling SMS messages.
1) Storing on SIM card
There are a couple of downsides with this option. You have to extract the SMS messages from the SIM card which costs time on the one hand. On the other hand it degrades the SIM card itself. Depending on how many SMS's you are receiving this could cause the SIM card to stop working aka no longer able to do read and writes.
2) Handling unsolicited
Here the downside is that you have to be permanently connected to the modem and collect the messages as they come. So if there are USB connection issues it could occur that you lose messages. There are ways of coping with this, for example by configuring the modem so that you manually acknowledge SMS messages received (AT+NACK). This means that the mobile operator network will resend the messages at a later point in time.
When you have modems from different manufacturers then configuration is sometimes a little tricky regarding unsolicited messages. Watch out there if you choose this route. Via AT+CNMI (parameters are different depending on manufacturer/model) you can configure how the modem deals with unsolicited messages. This also involves how the modem handles messages when no "host" is connected to the modem etc... I really recommend finding the AT Command manuals for your modems and seeing what is possible there.
To summarise I personally recommend the unsolicited approach as it's a lot more comfortable handling messages rather than accessing the SIM card to grab and delete received messages.
I have an SMS Appliaction, which receives the messages through GPS Modem and revert back through GPS Modem. The Modem is using COM1.
Now, i need two more appliactions which can send messages through the same GPS Modem. I tried making a webservice which can access the COM1 to send data, but when i try to connect through webService, it throw an error saying, 'COM1 is already occupied, Access denied.'.
Can anybody help me to connect through the modem in above scenario.
Khushi
You have to make sure only 1 connection is made.
Easiest (and most low-tech, but probably most flexible) is having a script checking a directory for files regularly and sending the messages in the file to the modem. The webservice then just writes a file for every SMS it received. (this can be trivially extended to accept emails, web requests, etc, ...)
A bit more sophistacated is to start a thread to do the communication and push the messages on a FIFO like datastructure provided by your favorite programming platform. A BlockinQueue would be perfect. The thread reads the messages from the queue and sends them to the GSM modem.
If you want to have confirmation the SMS is sent (which in my experience does not mean anything and certainly not that the recipient actually received it) you'll need to find a way to return feedback to the caller. This can be as simple a setting a boolean flag in the message to sending another message or performing a callback. But I would not bother. I had situations where 30% of messages dissapeared even when we had confirmation of the message central.