Smart Card Protocol Negotiation via Clock Frequency
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Solution Overview
Problem
The increasing demand for faster communication protocols in data carriers like smart cards poses compatibility issues with existing reader devices, as they often have interfaces tailored for low data rates, leading to the need for a negotiation procedure that minimizes disruption to the existing infrastructure.
Innovation Solution
A method where the reader device applies a clock signal with a frequency associated with the chosen communication protocol to the data carrier, allowing the data carrier to set the appropriate protocol, and vice versa, using existing contacts without altering the infrastructure or requiring a default protocol.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a communication protocol designed for low data rates is used to maintain compatibility with existing reader devices, then backward compatibility is preserved, but the data transfer rate becomes insufficient for current demands
Solution Approach 1:
The system dynamically selects between different communication protocols (T=0/T=1 for low data rates, T=1.5 for high data rates) based on the capabilities of the reader device. The data carrier adapts its communication mode by detecting whether the reader supports high-speed protocols, allowing the system to switch between protocol versions to optimize data transfer rate while maintaining compatibility with legacy devices.
2Ease of manufacture
If the interface is tailored for original low data rate demands to preserve existing infrastructure, then the present reader device/smart card infrastructure remains unchanged, but the interface cannot support present and future demands for faster communication
Solution Approach 1:
The data carrier is designed with multi-functionality to support multiple communication protocols (T=0, T=1, and T=1.5) within a single interface. The interface can operate in different modes depending on the reader device capabilities, allowing it to function both as a legacy low-speed device and as a high-speed communication device, thus making the interface universal across different protocol requirements.
Solution Approach 2:
The system performs preliminary detection of reader device capabilities before establishing communication. The data carrier detects whether the reader supports high-speed protocols in advance, and based on this detection, selects the appropriate communication mode before actual data transfer begins, preventing infrastructure conflicts while enabling future-proof performance.
3Adaptability or versatility
If a negotiation procedure is implemented to select appropriate communication protocols, then both legacy and modern protocols can be supported, but the complexity of the communication interface increases
Solution Approach 1:
The negotiation procedure is implemented in a self-service manner where the data carrier autonomously detects reader capabilities and selects the appropriate protocol without requiring external control or complex host-side negotiation logic. The detection and selection process occurs automatically during the initial communication phase, reducing the overall system complexity while maintaining multi-protocol support.
Data Source
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AI summary
A method of negotiating a proper communication protocol between a reader device (10) and a data carrier (20) is disclosed. In a first step, when the data carrier (20) is inserted into the reader device (10) at a first point in time (tl), the data carrier (20) provides information to the reader device (10), which communication protocols are supported by the data carrier (20), by means of a binary value (BV). In a next step, the reader device (10) chooses/sets one of the possible communication protocols according to its own capability. This choice is provided to the data carrier (20) by applying a clock signal (CLK) of a certain frequency (f), which is associated with the chosen/set communication protocol, to an input contact (C3) of the data carrier (20) at a second point in time (t2). Finally, the data carrier (20) sets the chosen communication protocol received from the reader device (10), thereby finalizing the negotiation sequence. Subsequently, communication may take place between reader device (10) and data carrier (20) from a fourth point in time (t4).