At present, the banknote and coin identifiers used in the popular general vending machines in the market are mainly based on the MDB communication protocol, which is serial communication. However, with the development of computer technology, the serial port has been gradually eliminated, and even the multi-serial port industrial control computer purchased at present cannot meet the requirements of the MDB protocol due to its own design defects. This converter follows the development of the trend, adopts the USB interface, and compared with other MDB conversion boards, it has strong versatility – it can directly use the MDB protocol standard, simple operation, plug and play, etc., and will not worry about debugging MDB equipment.
Using a new original imported FTDI FT230X scheme, the PC side USB to serial port TTL, and then through an independent microprocessor, re-modulate the malformed signal output by the host into a standard MDB communication signal.

In order to complete the basic function of communication between USB interface and MDB device, the following problems are solved：

• Ordinary USB to serial port cable, due to the byte spacing of the output signal, the MDB peripheral thinks that it has timed out and does not reply
• The check digit of the actual output signal of the multi-RS232 interface industrial computer is incorrect, which causes the MDB peripheral to think that the packet is wrong and does not reply
• The host fails to reply within the specified time of the MDB peripheral, resulting in the peripherals repeatedly sending the same information data

Fully tested to support the following products:

• MEI VN2000 Note Validator
• MEI Cashflow 7000 Coin Changer
• Conlux CCM 和 CLT Coin Changer
• CashCode CXB Note Validator
• NRI C2 Coin Validator
• CPI Gryphon Coin Changer