SMS callback service enables initiating connection between two telephone numbers by sending a text message from the user?s cell phone. SMS, sent to the access number, is transferred to the callback module, which, after having analyzed the instruction, contacts VoipSwitch with the task of connecting given telephone numbers. The number leased from SMS carrier or the cell phone with the SMS forwarder application installed can be used as the access number for the SMS callback service. In the first case, SMS carrier accepts all the incoming SMS and forwards them to the chosen URL address, using HTTP POST method.

SMS callback module receives the message with the information on the telephone number the message originated from and then, after having analyzed the command, initiates the appropriate operations.

In the second method, SMS sent from the client is received through the cell phone, connected to a computer with serial cable, with the SMS forwarder application installed (this application is provided along with the SMS callback package). The application reads each incoming text message and forwards it, with the information of the telephone number it was sent from, to the callback module, using HTTP POST method. SMS forwarder application can be installed on any given computer with the Internet access. That allows having multiple access numbers utilizing only one VoipSwitch.

After receiving the SMS, Callback module authorizes the client and, if it is successful, authorizes VoipSwitch to initiate connection with the numbers chosen. Incoming text message is authorized based on either the cell phone number, the message was sent from, or by checking login and password included in the massage. Below, there is a detailed list of the commands available for a client.

Incoming text message is authorized based on either the cell phone number, the message was sent from, or by checking login and password included in the message. Exemplary SMS text that would initiate telephone connection between two numbers (source and destination) can have the following structure:

U.callback P.pass D.48774417880 O.12345678

Where: U - denotes the username, P - denotes the password, D - denotes destination number, O - denotes source number.

User can register telephone numbers which are used for the authorization of incoming SMS by sending SMS of the following structure:

U.callback P.pass R.48600316058

Where R denoted the telephone number that will be used in the process of authorization. Another method of defining the telephone number used in the process of authorization is to register the phone number through the website at:

http://voipbillingrent.com

User has an option of registering unlimited number of telephone numbers. After having registered the cell phone number users do not have to provide login and password, unless they use different cell phone at the time.

D.48774417880 O.12345678

Above command, sent from the cell phone with the registered number (for the authorization purposes), will result in initiating the connection between two entered numbers - source and destination.

D.48774417880

Above command will result in initiating the connection between the cell phone the SMS message was sent from and the destination number (this option is only available with obtaining prior authorization based on the cell phone number)

I.

This command will result in obtaining SMS from the system with the up to date account status.

In the case of using non-registered cell phone the following message has to be sent in order to obtain information on the account status:

U.callback P.pass I. O.12345678

Where: O ? denotes the cell phone number the message should be sent to.

SMS callback users also have an option of using directory (telephone book), which can be managed through the web site at http://voipbillingrent.com or directly from the webcallback application.

After entering desired telephone numbers with the corresponding names, users can sent SMS in the form of e.g.

B.office

This message would result in initiating connection with the number that in the directory will be identified as "office".

Another way to initiate connection is to send "N" command with the number of the particular entry in the address book e.g. N2 will result in initiating connection with the number two entry in the address book.

SMS callback users can access the information on the telephone calls carried out on the web site at http://voipbillingrent.com.

SMS callback users can also make use of webcallback service and desktop version.

IVR for callback - IVR application (Interactive Voice Response) is provided along with Callback module,. Implementation of IVR in Callback module extends significantly its functionality. After having finished the call, or when the connection with the called party could not be completed (e.g. busy line, no answer), IVR acts as a voice prompt which informs the caller to dial another number he/she wants to connect with. Desired number is entered using the telephone's tone keypad (dtmf). In this way the person who initiates the call can carry out several calls without the necessity of re-launching callback every time. Also, the user can terminate the call without cutting of his/her "leg" by selecting the particular combination of digits (e.g. #1# , which is previous defined in VPConfig) with the telephone?s tone keypad. After terminating the previous call, caller is asked to enter another number he/she wants to connect with.

Additional feature which is supported by IVR is the voice information on the current account status. At any time user can choose a particular number, using telephone?s tone keypad, e.g. 111 (which is previously defined in VPConfig) to listen to the information on the current account status. In SMS callback service, the information on the account status is also available through sending SMS with the instruction ?I?. In addition the information on the current account status and detailed history of connections is available thorough the website

Accounts for SMS callback clients are added in the ?callback clients? menu. Callback clients can also use web callback, ANI callback and PC2phone services, provided they are authorized to use one account for PC2phone and callback services.

System has a tool for automatic generation of login/password pairs with an option of exporting data to the file and afterward managing the lots.

Callback's user has an option of logging to the website with detailed information on billing. There is also information on the current account status, detailed history of connections and possibility of exporting data to the file