Using gsm module in data mode

[BOB_SANTANA]

Using gsm module in data mode

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Hello All
Sorry to be a pain i just wanted to ask a dum question with regards to gsm modules.
i am happy in using them for sending and receiving sms manages but really wanted to know if it is at all possible to use the GSM module in Data mode with the pic.
i have large amount of data that would take lots of text msgs so was thinking of sending it all in one go.
Although the data sheet (See pg 2)for my module says it operates in Data Mode i just dont know where to start from.
http://www.omniinstruments.co.uk/rad...er%20guide.pdf
i have search on the internet but not having any luck
I need some of your expert advice on this as this is a grey area forme.
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BOB_Santana

[treitmey]

Your link doesn't go to a product. Which omni product are you using?

[BOB_SANTANA]

Sorry treitmey

i should have checked the link. i am actually using a wavecom Gsm modem
http://www.omniinstruments.co.uk/products/product/moredetails/wavecom.id270.html
the data sheet is below

http://www.omniinstruments.co.uk/radiotel/WM02user%20guide.pdf

All i really want to do is to be able to retrive the data that should have being stored in my serial eprom remotely without having to connect it to the pc .
_________________
BOB_Santana

[treitmey]

I can't help on this one. But start by writing or calling the tech support line and ask how to turn on "DATA" mode and download the eprom.
http://www.omniinstruments.co.uk/products/product/moredetails/wavecom.id270.html
bottom of page

[ckielstra]

Bob,
The product link you provide is for a Fastrack M1306B GPRS/GSM modem but the datasheet you link to is for the old predecessor WMOD2B which only supports GSM. What is the actual modem you are using?

Both modems can be used for a data connection, also known as CSD, but the newer modem supports GPRS which depending on your application can be faster, cheaper and slightly easier to implement.

If you do decide on the GSM data mode then here are some hints. Note that I use GPRS and am no GSM expert:
Get yourself a document or datasheet describing the AT commands supported by your modem. Most AT-commands you need are defined in the GSM Standard documents but there will be some exceptions and additonal 'nice to have' commands that are Wavecom specific. I didn't search for a WMOD02 AT commands document, but here is a link for the Wavecom Fastrack M1206B which should come close.

When calling a modem the network 'knows' if you are trying to setup a voice, data or FAX call. The numbering scheme for these call types is the same but are overlapping, i.e. for data and voice calls it is possible for your SIM card to have the same numbers, but it is also possible the data number for your SIM is different from the voice number. I once tried to call a data modem with my mobile 'voice' telephone and got connected to a normal person instead of to my modem. Was difficult to explain to her...

An introduction to the technical differences in how the network handles a data call: http://www.sarian.co.uk/assets/guides/html/AN_024_Making_and_receiving_CSD_data_calls_v1.0.htm

- Ensure your SIM card is enabled for Data calls (ask your provider). The provision of a data number is usually a separately-priced option that's not available to users of prepaid SIMs.
- Retrieve the Data number for your SIM (command AT+CNUM, or if this fails ask your provider).
- Appendix A of the AT Commands manual above has some examples for setting up the modem but more and better examples can be found on the internet when searching for some of the AT-commands.
- Note that there is only a small difference in the AT command for setting up a
data call 'ATD <phonenumber>'
and a voice call 'ATD <phonenumber>;' Note the terminating ';' character.

Try calling one GSM data number with another mobile. The most important thing is that both modems are running at the same rate, for 9600 use
at+cbst=7,0,1
at both ends.
Simulating an ISDN connection will give a much faster connect as there is no speed negotiation necessary but is not supported by all networks:
at+cbst=71,0,1

More reading:
How to make a GSM Data call
GSM FAQ

[BOB_SANTANA]

Thanks ckielstra

I am ready your reply and links with great interest.
You are right about the GSM module i have is the old WMOD2B which only supports GSM.
i am going to keep you posted in the mean time any other suggestion with regards to this project would be welcomed.
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BOB_Santana

[BOB_SANTANA]

Hi Guys
I have just checked with o2 my service provider and payg does not support Data mode.
so i am stuffed
is there any other way i can get around this .
Here is the project.
i have a data logger in the fields that logs my data and stores this to a serial eprom.
the logger is not going to be in range for any RF solution .
but i need to be able to download this data some how
what solutions do i have download speed is not importand it can be as slow as this would only be done every 6 months so i can live with that.
Please help
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BOB_Santana

[BOB_SANTANA]

just a thought
would this not be posible with a web server
[url]
http://www.coolcomponents.co.uk/catalog/product_info.php?products_id=78&osCsid=c8968a1e6a5caa3a78afd76cc877c885
[/url]
_________________
BOB_Santana

[Guest]

this could work for you but i havent used it lo
}www_ezweblynx_com

[ckielstra]

If you are willing to experiment: sometimes it is possible to get a data call working even when not supported by the network. For this you will have to setup the receiving modem for automatic answering:
ATS0=2 (automatic answer after 2 rings. Note last letter is a zero)
AT+CICB=0 (forces a data call when no incomming bearer is given)
And on the sending modem:
AT+CSNS=4 (forces a data call for outgoing)
Don't forget to setup both modems for the same baudrate (AT+CBST=...)

For the alternatives to data transmission:
How much data do you have to transmit on a monthly basis?
You are using pre-paid SIMs, and can't upgrade to another service providing data calls? Alternatives will cost money was well...

[BOB_SANTANA]

Ckielstra

Thanks for your suggestions and advice
i am willing to experiment and i would try those things out today
i can upgrade to a call monthly sim as a last resort lo:
Would that mean that i would have to both gsm modems on pay monthly?
I would only ever need to download the data two times a year as the data gets stored in the eprom and when it get full i get a text msg saying
that and i go to the site with my laptop and download the data then erase the eeprom.
the eeprom holds up to 6 months of data so its not going to be frequently used for making the Data Call.
But ckielstra would i not need a data Number for the data call?
i would like to do it your way .
i found this for example

http://www.tdc.co.uk/technical/downloads/faq/faq-04-01.pdf
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BOB_Santana

[BOB_SANTANA]

ckielstra

Just a quick question.
If i have my sim card enabled for data calls and attach the GSM modem to the instrument in the field.
would i not be able to dail into the modem from the modem that came with my pc or has it got to be another gsm modem.
i am getting lost now
_________________
BOB_Santana

[ckielstra]

I'm not an expert and things might be different between providers. I would make a test setup at your office with two modems and try out the combinations. With both modems at your desk it is easy to check the modem's result strings.

Tip:
If your office has an ISDN connection you can save a little money and get much faster connection setup using an ISDN modem. Make sure the ISDN modem supports v.110. Many newer modems only support v.120 which doesn't work. Setup the GSM modem with at+cbst=71,0,1