Vending Machine Telemetry (DEX/ MDB protocol) via wireless email/ftp

The idea is that this unit will be plugged into the DEX port, configured and not need to be touched. There may also be a credit card reader that will need to share the DEX port. Preferred to be powered by MDB or will consider battery/external power. Define hardware required, either off the shelf with minor modifications/connectors or custom combo. Unit to be located and secured inside the vending machine. Plug into 1/4 inch DEX jack, send email/ftp (how to configure/change) with wireless internet available at location. (lowest cost per unit desired) Configuration for each location. Set site ID maybe a serial number. Frequency to send data. Determine data size and time to transmit data. or always send every interval and calculate the minute to send (serial number / minutes in interval) remainder is the minute to start sending) or offer a beter option? Deploying how many units would this be a problem for what interval at the receiving end? File format to send data. Advantages/Disadvantages to always send in the same file format and then on the receiver's end look at the site ID and transform to other formats for processing after receipt? Best ideas for configuration will be reviewed, with the idea each unit will need a unique site ID or serial number and maybe a way to track that the file was successfully sent/received completed. Provide your ideas with your bid. Would this be a consideration to include on an EPROM? Your thoughts. Yes, Why? or Maybe, Why? or No, Why? Define csv file format, initially to Excel later to database. Design to include ability to easily add other file formats to send file. This will be to send data unattended so the location manager won't need to do anything once it is installed. Initially for about 30 machines for Proof Of Concept, later could be many more. 1. This is not intended to take any payments. 2. Is there existing hardware that will plug into DEX port and share it with a credit card reader? 3. This is intended to only send by email or ftp, from wireless connection, the DEX historical data for reporting. 3.1 No cell service available, therefore the wireless requirement. 4. This is to simplify and not require a physical visit to each machine to determine sales and restock needs.