It may not be simple, read this: Wire transfer - Wikipedia
Cellular service is over frequencies licensed from the FCC in the U.S.
However, what you are describing is a kind of work-flow process that will require considerable thinking; for example, what happens if the other device does not answer? What happens in the cellular network is down? How do you audit? How do you ensure transfer and subsequent consumption/usage/deposit/etc.?
Big companies spend big bucks on similar business-to-business (B2B) systems. You may wish to google 'B2B Money Transfer" to get an idea of the scope of the issue.
thank you my freind for this reply and well explanation
i think that i didn t know exactly how to present the idea
in my country i can recharge my phone credit from a small credit card
for example i have 100 usd on my phone after charging
now i can use this amount to call or i can send it again to a freind using my phone
some sellers start to sell this money
for example they sell 100 usd for 110 usd
they send it from the sim card and using the phone
for example i write this code in my phone
100+1986532*100 "usd" # and then make a call
my freind will receive a msg tell him that he received a credit in his phone he can use it now to call or send sms
my idea is that i want to make it automatically using arduino
now i can use this amount to call or i can send it again to a friend using my phone
OK, I get the general idea... there is a "fee" associated with the 1st transaction that represents a "cost" and after that cost, you could then subsequently send all or part of the amount to another number...
So, for example, if your SIM had a 100 credit, you could send a portion of this amount, maybe 20, to another SIM leaving you with a net of 80 to use or resell.
I have no experience with this technology, previous B2B was between businesses using encryption. My "feeling" is that an applicaton will be required on the GSM side (smartphone) to broker the transfer and ensure that the receiving side is credited and the sending side is debited and all the time ensuring that this is done via a smooth hand-off of funds... that is, one certainly WOULD NOT want the receiving side to be credited PRIOR to the sending side being debited ... that would be like printing money! In the same thought, one would NOT want the sending side to be debited unless the receiving side was credited. Thus, an application must be doing the handshake.
In my belief, such a complex application is unfit for an Arduino. However, an Arduino could be used to simulate the user input (security code, amounts, etc.) in an automated fashion so that the Arduino would be acting like a typist ... to the cellphone software. I just do not believe the Arduino can broker such a complex session to the GSM modem directly. Much more would need to be known before a final decision could be made, however.
For the community, I want to summarize the PM regarding this subject...
For a monetary transfer to happen (credits in this case) some mechanism must manage the process... The debit/credit issues between two units identified by the SIM card... That is, credits are "tied" to the SIM and not the handset.
We see this happen all the time with prepaid cellular. However, ikaz4ever is describing a credit transfer (real funds) between two SIM cards numbers based upon the telephone number of the receiver. Obviously, more must be going on and must be processing in a secure environment.
One may imagine that the two logical processing environments would be the handset (it has encryption capability and a CPU to run an application) or the GSM carrier providing the mobile service. As handsets are varied and have different OS's and are not "physically secure" the most likely place for all the processing to occur is the mobile carrier's facility.
IF the magic is totally SIM-card based, then all an Arduino would need to do is create the end-user message and use a GSM modem + SIM card that has the appropriate credit. Such a system could be constructed using the Arduino GSM library: http://arduino.cc/en/Reference/GSM and then tested.
Sometimes there is just no other way to work-in-the-dark other than to create a test case(s).
i want to make a simple machine for using arduino + gsm shield
a coin acceptor
when a person will insert money on the coin acceptor the gsm shield will send a message to a phone number
and i wants also that the machine will give the change and count money
the machine will be an sms sender for a mount of money
thank you for advance
i hope to hear from professional soon
06:41:30 am: i hope to hear from professional soon
06:47:39 am: why people always read and do not answer
You gotta be shitting us.
i want to make a simple machine
How is this a "simple machine", it seems reasonably complex to me.
The mechanics alone is a huge job unless you already have a machine you can hack. Is that the case? Is the coin accepter a module you can buy? If so that will help a lot, but how will you dispense change?