When the number is dialed from any of the number to LTE module, I got automatic responses from that module for e.g.
[2018-07-02 15:43:30:997_R:] DSR:0 CTS:1 (RI:0) DCD:0
[2018-07-02 15:43:30:997_R:] DSR:0 CTS:1 (RI:1) DCD:0
[2018-07-02 15:43:31:012_R:] NO CARRIER .
These are autogenerated responses without firing AT commands to the module. So I
don't want these responses. Please suggest me any AT command to stop this.
These responses are called unsolicited result codes because they are triggered by events other than AT commands.
To learn more about the different types of responses read chapter 5.7.1 Responses in the ITU V.250 specification. V.250 is one of the most important AT command documents and you should really read all of chapter 5.
Some of the unsolicited result codes can be individually disabled, but some (e.g. NO CARRIER) cannot, so you must write your modem software to handle them. There is no way around.
Related
I want to send an information to web server with arduino via sim800l.
AT+HTTPPARA=\"URL\",\"http://api.trackers.live/v3.0.0/TRCKR02B2AF359D19/40.35715122342342322432-36.077406243242342-1469134234/1212/021/16553"
When I want to send long url to web server,the program crashes.
Does sim800l has an url limit? or is there any possible way to send an url like this?
Yes, all modems have a limit in how many characters they accept on a command line. The V.250 specification says in chapter "5.2.1 Command line general format":
A command line is made up of three elements: the prefix, the body, and the termination character. ... The DCE shall be capable of accepting at least 40 characters in the body.
The prefix is the two characters "AT" or "at" and the termination character should be '\r', thus a modem (aka DCE, Data Circuit-terminating Equipment) is allowed to only accept as low as 43 characters on a command line.
Now the was majority of modem supports more, probably that 40 character limit was due to some old Hayes modem made in the 1970s. If sim800l has decent documentation it should say how many characters it support on a command line. If it has crappy documentation it will not say.
As always with AT command syntax question, the very first source to query should always be the manufacturer specific documentation for that particular modem. Failing that you can fall back to V.250 or 27.007 or 27.005.
I dont know about the limit but you can use a link shortener to shorten the link...
I am using Putty to simulate my phone's modem connected via serial. When my phone receives a call it outputs 'RING' into putty but when the caller cancel the call Putty doesn't out put any response or result.
How would the modem know that the caller disconnect/cancelled the call, but not output it in putty?
Thanks
To detect missed calls you can try three things.
Check if there is a suitable AT+CIND indicator you can turn on. I do not think call will do since I assume it only goes to 1 when the call is answered. If your phone supports callsetup or something similar that should be what you need (you will have to implement logic to detect when a call does not go to state active).
For an example of enabling AT+CIND indicators, see chapter "8.57 Informative examples" in 27.007 for more explanation, and pay close attention to The subparameter order in the command is defined by the query command order, e.g.
if AT+CIND=? returns
+CIND: ("abc",(0-1)),("xyz",(0,1)),("call",(0,1))
then call is index 3, and for
+CIND: ("abc",(0-1)),("call",(0,1)),("xyz",(0,1))
call is index 2. Do not hard code any assumptions here, this should be parsed and checked run-time (one check at the beginning is enough).
Alternatively you can upon RING start polling call status with AT+CLCC until the call is no longer listed.
Or you could poll the MC phonebook storage and detect changes.
Most modems show the incoming phone number and a RING when a call is received and an END when the call is cancelled. To view the missed calls, you may use the following AT Commands.
AT+CPBS="MC"
AT+CPBR=1,99
First command tells the modem to look in the missed call phone book and the second command loads entries from 1 to 99. Note that this behavior is not standard. I was able to replicate this on a GSM module but not on my 3G modem. Try it on your modem and check if this works. All the best.
I want that my MC52i auto accept an incoming call. If I use AT commands to answer manually (ATA) it works fine, but I'm not able to force the modem auto accepting an incoming call. On other devices it works with ATS0=1 but not on the MC52i. I think it has something to do with the GPRS Mode?
What type of call are you trying to accept, voice or CSD? Setting S0 ought to be enough for this. Try to enable AT+CRC=1 and examine the +CRING: <type> unsolicited result code (see 27.007 for details). Does it fail to auto answer all incoming calls? Try to have it auto answer both voice calls and data calls. Try to call from PSTN, ISDN and mobile phone (both same operator and different operator. Try several different phone models). If it fails to answer all those cases then you probably have to write off auto answer as a possibility. Oh, by the way, also try with several different sim cards (from at least more than one operator) in the modem to rule out problems with the operator/subscription.
I have probably given enough options to tweak so that testing every single combination is not feasible and useful, but pick some variations of all of them and set up at least 20 different test cases.
Although very unlikely, I'll mention the following for completeness and as a background to one of the many reasons why testing with several different operators is important:
There could be a problem if the network does not include call type information in the Bearer Capability in the SETUP message and then the phone does not know how to answer the call. This is very unlikely today, but several years ago some network could behave so. Because of this the phones used to have a "receive next call as" configuration to determine how to behave then. But I assume all newer phones to just ignore this scenario (It was applicable back in the days when Ericsson made mobile phones in their own brand, at least I remember seeing seeing this configuration option in their single menu style phones like T28. I do not remember if it survived the conversion to the icon based menus).
Im working on a program to send and recieve SMS using a GSM modem and my computer.
I have gotten sending and receiving to work - well sort of.
Once in a while my program is sent into a total chrash due to modem is mixing up information about Radio Signal Strength Indication and alike, while also serving my program with the hex code for the message.
My code can handle the hex code just fine. but I have seen the following line popup while im decoding a byte stream:
^RSSI: 2
So far I've seen it send out values between 1 and 10.
Is there an AT Command that can disable them? I have no need for them.
Or alternative: Is there a general syntax for them, so I can filter them out before decoding?
Im leaning towards a filter solution. But that would be more easy to implement if I knew whenever modem is sending out on the form: "^SOMETHING: xxx", then It would be nice to know if it is always followed up be a delimiter say for instance "\r".
You should try turning off periodic messages as using AT^CURC=0.
Information regarding the AT^CURC command:
AT^CURC? Current setting of periodic status messages
AT^CURC=? See what you possible values are
AT^CURC=0 turn off periodic status messages
The best way to tackle this scenario would be to replace that part of the response with an empty string because otherwise, it will be difficult to check even if the command sent to disable it is working or not.
This regex will match all those. You can replace them ideally by an empty string.
(\\n|\\r|\\r\\n)\\^.*(\\n|\\r|\\r\\n)
How do I discover how many bytes have been sent to a TCP socket but have not yet been put on the wire?
Looking at the diagram here:
I would like to know the total of Categories 2, 3, and 4 or the total of 3 and 4. This is in C(++) and on both Windows and Linux. Ideally there is a ioctl that I could use, but there doesn't seem to be any.
Under Linux, see the man page for tcp(7).
It appears that you can get the number of untransmitted bytes by ioctl(sock,SIOCINQ ...
Other stats might be available from members of the structure given back by the TCP_INFO getsockopt() call.
Some Unix flavors may have an API way to do this, but there is no way to do it that is portable across different variants.
If you want to determine wheter to add data or not: don't worry, send will block until the data is in the queue. If you don't want it to block, you can tell it to send(2):
send(socket, buf, buflen, MSG_DONTWAIT);
But this only works on Linux.
You can also set the socket to non-blocking:
fcntl(socket, F_SETFD, O_NONBLOCK);
This way write will return an error (EAGAIN) if the data cannot be written to the stream.