I can't take a HTML page with SIM800L GSM modem.
I open connection
AT+CSCS="GSM"
AT+CMGF=1
AT+SAPBR=3,1,"APN","apn.fastweb.it"
AT+SAPBR=1,1
AT+SAPBR=2,1
+SAPBR: 1,1,"10.44.96.11"
I define HTTP param:
AT+HTTPINIT
AT+HTTPSSL=1
AT+HTTPPARA="CID",1
AT+HTTPPARA="REDIR",1
AT+HTTPPARA="URL","https://www.gevaelettronica.it/"
AT+HTTPACTION=0
+HTTPACTION: 0,606,0
SSL is working
AT+HTTPSSL?
+HTTPSSL: 1
IP there are:
AT+SAPBR=2,1
+SAPBR: 1,1,"10.44.96.11"
AT+CIFSR
ERROR
if error, need to check PDP parameter.
What is PDP ?
AT+CGDCONT?
+CGDCONT: 1,"IP","","0.0.0.0",0,0
+CGDCONT: 2,"IP","","0.0.0.0",0,0
+CGDCONT: 3,"IP","","0.0.0.0",0,0
Nobody uses this command +CGDCONT
AT+CGDCONT=1,"IP","apn.fastweb.it"
AT+CGDCONT?
+CGDCONT: 1,"IP","apn.fastweb.it","0.0.0.0",0,0
+CGDCONT: 2,"IP","","0.0.0.0",0,0
+CGDCONT: 3,"IP","","0.0.0.0",0,0
AT+CIFSR ERROR
expected is
+HTTPACTION: 0,200,0
PDP is short for Packet Data Protocol, and is used in mobile network context in relation to packet switched data communication (as opposed to circuit switched communication). The first evolution of support for this was called GPRS in late 90's/early 2000's. Later technological successors were UMTS and LTE.
For more details there is a whole chapter 10 Commands for Packet Domain in the 3GPP 27.007 specification which is rather technical - after all the specification is indented as a specification with all required details for companies to implement phones/networks supporting the technology, although it also describes the behaviour and parameters of the packed switched commands like AT+CGDCONT etc, so it is kind of important and useful information as well.
So by all means read it, but do not set your expectation that you to be able to read the whole chapter and fully understand all the details. I think the best approach is to start reading the description for each of the commands you are using, and then "expand outwards" as needed (that's how professionals read those specifications. Nobody starts on page one and reads all the way till the end (unless your assignment is and you are paid to proofread I guess)).
I was not highly involved in packet switched data communications, so I do now know/remember much more details than I have written above. If on the other hand you have questions about mobile circuit switched data calls, boy can I give you more detailed answers!
Related
I bought a Simcom (Sim7080G) module to use it for geolocation and send data over TCP. These modules are quite new on the market (it was first launched in mid 2019) and there is some weird functionning with it. I would like to know if people that use it struggle with the same problem.
My goal is to take GNSS (latitude/longitude) informations, and to send them over TCP.
Activate and take GNSS informations
AT+CGNSPWR=1
returns OK
AT+CGNSINF returns +CGNSINF: 1,1,20200517191239.000,4x.xxxxxx,6.xxxxxx,473.769,0.00,,0,,1.9,2.1,1.0,,7,,7.9,6.0
Connect to any TCP server
AT+CNACT=0,1 returns OK\r\n\r\n+APP PDP: 0,ACTIVE
AT+CAOPEN=0,0,"TCP",151.101.1.69,80 (151.101.1.69 is stackoverflow.com ip address)
--> Some time waiting (like +40s) and then:
+CAOPEN: 0,23\r\n\r\nOK
The code 23 means: 23 Remote refuse, but in my case the connection never reached the server.
Only GNSS or TCP can be used, but not both
What is weird about all of this, is the fact that I can connect on a TCP server, but this stops to work when I activate GNSS.
I sent an email to Simcom technical support.
After insisting that my problem be addressed by a Simcom engineer, I received an answer. I encouraged them to be more clear on their documentation because this information was nowhere (this module is pretty new so I think they missed it on documentation).
Hope to help somebody in the same way or not to do the same pricey error:
Hi Dardan,
"it is not possible to use GNSS and TCP at the same time"
This is known limitation for this module, as there are limitation for
LTE and GNSS part, they can not run simultaneously because they are
sharing part of RF components(SIM7070G low cost version of SIM7000G)
so it is time MUX for LTE and GNSS which means the GNSS performance
could not be good(if customer needs to send GNSS data to server in
very short interval such as <10 seconds), for SIM7000G LTE and GNSS
can work simultaneously without problem. so SIM7070G could be a good
solution for "parcel tracking" etc, which do not need the continue
navigation. please go for SIM7000G, thanks.
xxxx Sun
I found this issue some hours before read this post. My product publishs in AWS IoT MQTT broker; it works, but I need the GPS coordinates to be sent together in message. I'm a lot frustrated, because such problem should be said in Simcom's documents. My previous version was using sim7600g, more expensive, but works fine. I live in Brazil, everytime I need to test some different module I loose more than 1 month to buy from China or somewhere and arrive a new one to me. I tried to turn ON/OFF GNSS and the TCP conection in alternate way, but is too slow the process to reconnect on gsm network.
Ran into this as well. With MQTT it is possible to power down the GPS unit to be able to send and receive MQTT messages without reconnecting/subscribing to the broker again. I've made a 30 second interval to enable/disable the GPS unit and tested it with HiveMQ public broker. Receiving of position data every 60 seconds is possible with this setup, which might be sufficient for some applications. For the price, it has this is still a good module.
I receive no response for HTTP Get request for the http://httpbin.org/get URL. Following is the output using the AT Command Tester from https://m2msupport.net
Checking registration status...
AT+CREG?
+CREG: 2,1,"912","3D73",0
OK
The device is registered in home network.
AT+CGREG?
+CGREG: 2,1,"912","3D73",0,"1"
OK
The device is registered in home network.
Device is registered..
Check the network APN...
AT+CGNAPN
+CGNAPN: 0,""
OK
Network did not send APN to the device.
Activate the network bearer...
AT+CNACT=0,1
OK
+APP PDP: 0,ACTIVE
Set up the HTTP URL...
AT+SHCONF="URL","httpbin.org"
OK
Set up the HTTP body length...
AT+SHCONF="BODYLEN",1024
OK
Set up the HTTP header length...
AT+SHCONF="HEADERLEN",350
OK
Initiating HTTP connection...
AT+SHCONN
OK
Get the HTTP connection state...
AT+SHSTATE?
+SHSTATE: 1
OK
HTTP connection is successful...
HTTP get request...
AT+SHREQ="http://httpbin.org/get",1
OK
No reponse received..
I am communicating with a server from Verifone Nurit8320(DTE) via siemens MC55 gsm modem(DCE).
I am passing AT commands via UART to give commands to siemens MC55 gsm modem (DCE).
I have given a delay of 100 ms (required) between every AT command and I am flushing the UART of DTE before sending any command on it.
Now the problem is this
In many cases DCE is responding with the response of the previously executed AT command. The DCE UART is never flushed.
Where can I get the set of AT commands so that I can flush the UART buffer of DCE?
The problem you are trying to solve (flushing the DCE UART) is the wrong problem to focus on, because it is a problem that does not exist in AT command communication.
After sending an AT command to the DCE you MUST read every single character sent back as response from the DCE, and parse the text until you have received a Final Result Code (e.g. OK, ERROR and a few more) before you can send the next AT command. Any other way is doomed to bring in an endless list of problems and will never, never, ever work reliably.
See this answer for a general outline of how your AT command sending/parsing should
look like. Using a fixed time delay should never be done; it will either abort the command or in best case waste time while waiting unnecessarily long while never removing the risk of aborting despite of waiting. See this answer for more information about abortion of AT commands.
I'm working on the firmware of a device that is going to be connected to PCs using Bluetooth in serial port emulation mode.
During testing, I found out that modem-manager on Linux "helpfully" tries to detect it as a modem, sending the AT+GCAP command; to this, currently my device replies with something like INVALIDCMD AT+GCAP. That is the correct response for my protocol, but obviously isn't an AT reply, so modem-manager isn't satisfied and tries again with AT+GCAP and other modem-related stuff.
Now, I found some workarounds for modem-manager (see here and thus here, in particular the udev rule method), but:
they are not extremely robust (I have to make a custom udev rule that may break if we change the Bluetooth module);
I fear that not only modem-manager, but similar software/OS features (e.g. on Windows or OS X) may give me similar annoyances.
Also, having full control over the firmware, I can add a special case for AT+GCAP and similar stuff; so, coming to my question:
Is there a standard/safe reply to AT+GCAP and other similar modem-probing queries to tell "I'm not a modem, go away and leave me alone?"
(making an answer out of the comments)
In order to indicate I do not understand any AT commands at all (aka I am not a modem) the correct response to any received AT commands should be silence.
In order to indicate I do not understand this particular AT command the correct response should be ERROR.
Anything between will trigger implementation defined behaviour of the entity sending AT commands. Some will possibly give up right away while modem-manager apparently is set on retrying sending the command until it gets a "proper" response.
I m trying to access a website using sim900 GSM module.
This is the list of commands
AT+CSQ
+CSQ: 16,0
OK
AT+HTTPINIT
OK
AT+HTTPPARA="CID",1
OK
AT+HTTPPARA="URL","www.google.com"
OK
AT+HTTPACTION=0
OK
+HTTPACTION:0,601,0
AT+HTTPACTION=0
OK
+HTTPACTION:0,601,0
Unable to access google. 601 code shows Network error.
How to get rid of this error?
You need to setup the connection to the bearer. Here are the minimum setup commands that have worked for me (based on trial/error and searching around on the internet).
AT+SAPBR=3,1,"APN","wap.cingular"
AT+SAPBR=1,1
The correct value for the APN may be different for you, depending on your network and service provider. I'm using AT&T prepaid SIM cards. Once that's working, then you can do the HTTP setup commands as you already have...
AT+HTTPINIT
AT+HTTPPARA="URL","http://www.google.com"
AT+HTTPACTION=0
Status codes above 600 (and some in the 500 range) are unassigned in the HTTP standard. In the AT command manual for the SIM908, status meanings are given in the notes on the HTTPACTION command:
600 Not HTTP PDU
601 Network Error
602 No memory
603 DNS Error
604 Stack Busy
You can query the bearer connection status of CID 1 with AT+SAPBR=2,1 and the related parameters with AT+SAPBR=4,1. You can also check that you're attached to the GPRS network with AT+CGATT?. If everything indicates that you are connected and you are still getting a 601 status code, then check that your service plan has data and that it hasn't run out. I have found that even when my account has a few hundred k of data showing on the balance that I start to get a 601 status until I add more data to my prepaid phone plan. If the SIM module has been on the whole time and you add more data, you'll need to close and re-open your connection (AT+SAPBR=0,1 followed by AT+SAPBR=1,1) and then your HTTP* commands will start working again without having to set the HTTPPARA settings again and without having to restart with HTTPINIT.
I have found that when an http call is made to an https only website it will throw a 601 error on the sim. Beware some sim devices have ssl and some don't. Use AT+HTTPSSL=? to interrogate. device with ssl will respond like, 'HTTPSSL 1'. If you get an error your device doesn't have ssl. This took some work with the factory for me to determine this.
You must also use to hit ssl site. I am using the wifi101 ssl client.
fona.setHTTPSRedirect(true);
dy3
I have encoutered this error as well. The cause of the problem may be that there is not enough money in the phone number account. You may check it.
601 is some custom implemented Error code.
Here is the list of standard HTTP Status codes
+HTTPACTION:0,601,0
The above AT response code (601) for HTTP session start indicates that
there is a network error. Then make sure that the PDP context is setup
properly.
source
https://m2msupport.net/m2msupport/at-command-for-http-functions-for-remote-server-data-access/
I have spent many hours with this module right now.
My experience is that when you dont get a 200 reply from remote server, you should check IP address to verify you are still on the network sendng a ping to a working server (AT+CIPPING="XX.XX.XX.XX").
If it succeeds: Try AT+SAPBR=2,1 and AT+CIFSR. You should get same address for both commands.
If you dont get same address, login again to the netword/service with AT+CIPCSGP=1, "yourapn.com", "user", "password".
If nothing works, power down the module. Wait a couple of minutes, and restart again.
Just in case someone is affected by this problem and stumbles on this post 4 years later: in my case the module had a small "sticker" type antenna and it got somehow damaged.
I could connect to the network but when I tried to use HTTP over the GPRS networks I only got return code 601 (network error) or 603 (failed to resolve DNS).
Once I replaced the antenna with a new one, everything worked perfectly.
Again, in case somebody has the same problem. In my case it was a typo in url:
AT+HTTPPARA="URL"," http://www.google.com"
Did you notice the space before http? For several hours, I didn't notice it too.
Usually after this command AT+SAPBR=3,1,"CONTYPE","GPRS" you enter your "APN", "USR" & "PWD" details also using SAPBR=3,1 etc. These details must match the SIM card / mobile phone provider.
Then it is recommended to check that your device has now received an IP address. Sometimes this is not straight away. Use AT+SAPBR=2,1 to query and this will return your IP address which you should check for confirmation.
Once you have IP address you can enter AT+HTTPINIT, AT+HTTPPARA="CID",1 etc.
Now to use GET you have to include a "?" after the URL to provide your php script with a key=value pairing.
Thus in your case it is something like, AT+HTTPPARA="URL","http://<Public_Ip_Address>:8080/folder/savedata.php?A=1001" where A is the key and 1001 is the value.
Now send the AT+HTTPACTION=0 and you should get a +HTTPACTION: 0,200,1000 response where 200 is the OK and 1000 is the payload size. AT+HTTPREAD will allow you to read the response if it is required.
Change URL. 601 is a URL has been moved. Is a redirect.
Mainline DHT is the DHT used by BitTorrent, which implements an RPC protocol over UDP called KRPC. KRPC includes support for error messages outlined here.
Why is this necessary? As this is an unreliable protocol, there is no guarantee of these messages being received, as well as the fact that there is no apparent use to them.
If you send malformed messages to a node, it may be helpful for that node to return an error message so that you can fix your code, instead of pretending the message wasn't received.
If every node would respond with error messages, client developers would have a much easier time fixing bugs in their DHT implementations.
As far as I know, only libtorrent (rasterbar) and the original BitTorrent Mainline (python version) send error codes in the DHT. It's possible other clients do, but primarily, uTorrent doesn't.
Update:
The error codes were extended in the put/get extension to be used for atomic writes. When updating a slot in the DHT, an error message may inform the writer that the slot was updated in between reading-updating-writing it, and that it should try again. This is referred to as CAS in the specification (named after the CPU operations compare-and-swap).
This extension is supported by uTorrent, libtorrent and Bleep.