Calling Card Dialer

Automatic dialer for calling card. As part of one of our projects, we are looking for an experienced telecommunications electronics. Our project involves the construction of an automatic dialer for calling card meets all safety standards in force in this sector. The first part of this project is the realization of the electronic diagram of the product. So that you understand correctly what we want to achieve, we will briefly explain how the product works. The product is physically placed between the user's phone and the wall outlet telecommunications provider. If a call is incoming, our product will do nothing and be completely transparent to the user. In the case of an outgoing call, when picking up the telephone, our product will give the dial tone dial the phone number. This operation must be performed without physically connecting the user to the telephone line. When the user has finished dialing his phone number, our product physically connect the phone line and dial sequences calling card to route the call to. In summary, the user dials the desired number and then our product communicates with the core of calling card to save the cost of communications. We have selected some components that must be in the diagram. These components are: IXYS Litelink III CPC5622 - Insulation barrier according to the protocols in force internationally . $ [login to view URL] file/[login to view URL] IXYS CPC5602 - Mandatory with the CPC5622 . $ [login to view URL] file/[login to view URL] HOLTEK HT9170B - DTMF Receiver [login to view URL] HOLTEK HT9200B - DTMF Generators [login to view URL] FTDI FT232R - USB UART - Allows to connect our computer-generated. [login to view URL] MICROCHIP PIC18F46K20 - Microcontroller performing product management. [login to view URL] The following pins of the microcontroller are already operated : RE0 - RE1 - RE2 (For LEDs ) The PORTC ( RC0 - RC1 - RC2 - RC3 - RC4 - RC5 - RC6 - RC7 ) are used for USB ( RC6 - RC7 ) RS232 communication For the rest of the schematic , everything is possible. The PORTA - PORTB - PORTD are currently free so you can connect other components. I stay at your disposal for any additional information and suggestions.