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tc35 gsm modem related question

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polarized

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siemens a35 at commands

Hi,

I have a question regarding the tc35 gsm modem. I managed to configure the modem in a way that it transmits the received SMS messages directly to its serial port instead of storing them on the internal SIM card.But after receiving each SMS message you have to acknowledge it with a specific AT command AT+CNMA. If this is not done, the tc35 is not in the mode in which the next received SMS message comes out on the serial port. The sms message is again stored on the sim card. So, what is the problem you will ask: if a whole group of SMS messages from different objects is transmitted from the SMS service centre at once towards the same gsm modem, I mean one after other quickly and rapidly, how can I manage to acknowledge each message. Would it be a good idea to use some kind of flow control like RTS and CTS nad is it possible to use the flow control when dealing with SMS messages? How deep is the internal buffer of the TC35 gsm modem? And also do you know how long is the period of the acknowledgment timeout?


Thanks.
 

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siemens a35 at command

hi ...

first of all .. you should write your apps that it will receive and buffer sms as first priority and will parse it later. receiving sholud be interrupt based ... second ... even in case that sms is stored to sim you can read it from sim and delete it from sim .. only disadvantage is that sim storage is limited. do not hesitate to reply when you need additional infos ...

regards

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tc35i send message pdu format

Hi Cancel,


I did not quite understand you. I would like to receive all of my SMS messages on the UART port, because to me it looks quite easier. On the other hand the SIM card is limited by its memory size, as you said. My problem is that lets say 50 different objects would send some data via SMS towards one GSM modem at the same time. It is not necessary to build the system in this manner, I could divide them into separate time intervals, but for the moment I plan to do it in the above described way. I wanted to ask some of you did anyone try to receive SMS messages in a manner like this when they come quickly and rapidly and can I interrupt a serial sequence like this with my acknowledgment command and are modems really full duplex machines?

Bye.
 

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siemens tc-35i gsm modem forum

I do something similar with Siemens GSM phones (much cheaper than GSM modems).

Depending on the type they buffer at least 10 SMS messages on the phones sim. As far as I know the GSM systems also buffers outstanding SMS messages (at least for 7 days) until the phone (modem) is ready to accept them.

It is no problem to retrieve one SMS after the other from the phone (Sim).

hope this helps ...
 

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how to send sms the greek char xi tc35

Hi,

Can you send sms messages in text mode using ordinary Siemens mobile phones or you use the PDU mode? Do you use the phones together with microcontrollers or you use them with PC machines? How complicated is the PDU mode if you use it and what commands do you use to for example send an SMS message or to receive one?

Regards.
 

C-Man

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<cr> modem tc35i

Siemens phones only support PDU mode.
I am using the phones together with 8051 and Pic microcontrollers.

Look for my posts and you will find a lot about this.

I do not remember the commands exactly but I will look them up for you and post them here.

regards
 

C-Man

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tc35 at+cnma

OK, here we go:
to check if the phone supports SMS (A50 does not!) "AT+CSCS=?" answer from the phone "OK" or "ERROR"

send SMS "AT+CMGS=" and here comes the tricky part phones before C45 are satisfied with a fixed "160" afterwards, newer phones want to know the exact lengt of the following PDU (unly userdata) in Oktets ...

after receiving this the phone answers with ">" afterwards you can send the pdu and to finish the whole process CTRLZ (0x1A)

answer from the phone (can take a few seconds) "OK" or "ERROR"

receive SMS "AT+CMGL=" and "0" for new SMS or "1" for SMS stored in the SIM

phone answers with:
+CMGL: 2,1,,155
0591347......

OK

which means SMS received the internal number is 2 (you need this later)
the following lines are the received PDU.

Problem is here that if more than one SMS was received (second number after the "2" in this case) you get all the PDU's for them too.

To simplyfy receiving I only read the first of X received SMS

After decoding the SMS you have to delete this SMS from Sim memory using the internal number (from above) "AT+CMGD=" and the above number (in this example "AT+CMGD=2")

answer from the phone "OK" or "ERROR"

or the phone answered just "OK" after "AT+CMGL.." which means nothing received

if SMS was received with this method you will have to repeat the above process with "AT+CMGL=1" which means stored SMS until you just get "OK" otherwise you do not realise if more than one SMS was received.

Please note that it took me to weeks to figure everything out and I post it here only because I also got help here often ...

best regards
 

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gsm modems siemens hayes wiev sim number

Hi,

This is good stuff that you post on the forum. I have a couple of questions more. When decoding the PDU sequence is it possible to use the following logic: I start from the most right position and when I approach the character which has a value which is the same as the number of characters I traveled from the most right position to the left I "proudly" conclude this is my data message codded in PDU format. Now, I have to decode it using the inverse rules how it was coded. Another question: I have a short example of decoding PDU messages, but only for 3 letters, "GSM". Of course, real world SMS messages are longer. What happens when I approach the 7 letter border? Do I start from the begining in the same fashion I coded the first 7 ascii letters? I mean the "rolling" technique.


Regards.
 

C-Man

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pinout tc35

try this neat program, helped me a lot:
hxxp://www.nobbi.com/download/pduspy.zip

many etsi GSM standards can be downloaded here:
hxxp://pda.etsi.org/pda/AQuery.asp

this also helped me a lot:
hxxp://www.nobbi.com/sms_pdu.htm

also look here:
hxxp://www.elektroda.pl/eboard/viewtopic.php?t=41401&highlight=pdu

I have also included my decoding routine for PDU (sorry for the comments which are in German) so you can get the idea.

it takes some time until everything works as supposed ...
 

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microcontroller to tc35i

Hi,

What is the easiest way of finding out the actual SMS message lenght. I do not need all of the parameters like the origin number, time stamp etc.. The only thing from the PDU sequence I need would be the actual message composed from ascii characters. I know that the characters are located on the right side of the PDU sequence. How can you calculate the data lenght by examing the PDU sequence?


Regards.
 

C-Man

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siemens a35 commands

In theory it works like this:

You start having the complete PDU in a buffer (the pdu must already be in binary format that means "AABBCCDDEE" must equal to 0xAA, 0xBB, 0xCC, 0xDD, 0xEE).

Start by reading the first byte in the buffer (which is actually length of adress of SMSC) you add 2 to this value and use it as a pointer into the buffer (I assume the buffer starts at offset 0 as is usual in C).

Now the pointer points at lenght of destination adress.

You again read this byte add it to the pointer and finally add 9 (this skips protocol identifier, data coding scheme and timestamp.

Now the pointer must point to the lenght of userdata (which is counted in septets) when reading this value you should have your message lenght.

Please verify if everything is correct, I have only extracted this from my program ...

best regards
 

kyoko

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program receives nothing from gsm moden

hi, i have buy siemens ME45 data cable and try to get older siemens phones like c35i, s25, s35i r the data cable compatible for all this phones?r this few model support at command?i hav try test siemens C25 with AT command using hyperterminal but i didnt receive any response.
 

C-Man

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c#+sms+pduconverter+smscaddress

kyoko

it should work (at least with c35 and s35) use 19200 baud 8 bit 1 stop bit no parity no handshake.

best regards
 

kyoko

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source c tc35i pic

Hi,C-man
at my place i only manage to find siemens M55 it support AT command? and i have the siemens ME45 data cable.
Thanks
 

C-Man

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what is tc35

kyoko said:
Hi,C-man
at my place i only manage to find siemens M55 it support AT command? and i have the siemens ME45 data cable.
Thanks

Yes M55 supports AT commands and also has a "soft modem" built in.

BUT the M45 cable will not work because M55 has the "new" slim lumberg connector (different mechanical size different pinout) ...

best regards
 

kyoko

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cable pinout tc35

Hi C-man,

I've started using pduspy with Ericsson T28 phone but i still can't get the message sent to my phone. What are the normal settings to send message from PC to the phone?
 

C-Man

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tc35 cable pinout

Sorry I am not using Ericson phones and I do not know if they support AT commands and PDU format.

Some phones support only AT commands at 115000 baud maybe try this baudrate.

best regards
 

kyoko

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microcontroller tc35i program

Hi,c-man. I have test the hp with hyperterminal n already know how to send n read sms using it but my problem now is how to program the pic so that it will tell the hp to send sms. Can u give me some example?i using c language wif PICC n using pic16f84. pls help as i newbie at tis area. Thanks a lot
 

C-Man

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tc35i at command sequence

kyoko,

did you read my posts here in this thread??

You should find everything you need by following the links I gave ...

Also if you want to make life easier for you use 16F628 instead of 16F84 because it has a hardware UART built in.

best regards
 

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