Protocol Selection for Chip Card Terminals
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing communication protocols between terminals and portable data carriers, such as chip cards, are inefficient for transmitting large amounts of data, especially when different protocols are supported by the terminal and data carrier, leading to slow data transfer and complex contact assignments.
Innovation Solution
A method is introduced where the terminal sends requests to agree on a communication protocol, initially attempting the SPI protocol during the undefined state of the ISO 7816 protocol, and if unsuccessful, switches to another protocol, ensuring faster data transfer by utilizing the SPI protocol's higher speed and full-duplex capability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the terminal attempts to establish communication using the first communication protocol (e.g., SPI) during the undefined state of the second communication protocol (e.g., ISO 7816-3), then the data transfer speed is improved, but the reliability of protocol agreement deteriorates because the second protocol is in an undefined state
Solution Approach 1:
The terminal performs preliminary protocol selection during the undefined state period of the second protocol by sending requests according to the first protocol before the second protocol becomes active. This preliminary action secures a faster communication channel before the slower protocol takes over, resolving the contradiction by acting in advance during the window of opportunity.
Solution Approach 2:
The system dynamically switches between two communication protocols based on the operational state. During the undefined state of the second protocol, the first protocol is used for initial communication; once the second protocol becomes defined, the system transitions to it. This dynamic adaptation allows the system to exploit the speed advantage of the first protocol while maintaining the reliability of the second protocol for subsequent communication.
2Reliability
If the terminal waits for the second communication protocol to become defined before attempting communication, then the reliability of protocol agreement is improved, but the data transfer speed deteriorates because communication is delayed
Solution Approach 1:
Instead of waiting passively for the second protocol to become defined, the terminal performs preliminary communication actions using the first protocol during the undefined state period. This eliminates the delay that would otherwise occur while waiting for protocol definition, thereby improving speed without sacrificing reliability since the preliminary actions are designed to be compatible with the eventual second protocol state.
Solution Approach 2:
The system maintains continuous useful action by initiating communication requests during the undefined state rather than idle-waiting. The terminal continuously sends requests according to the first protocol throughout the undefined period, ensuring that communication proceeds without interruption or delay, thus maintaining both speed and reliability.
3Adaptability or versatility
If multiple communication protocols are supported by both terminal and data carrier, then the adaptability is improved, but the device complexity deteriorates due to multiple contact assignments and protocol management
Solution Approach 1:
The terminal and data carrier are designed with multi-functional capability to support multiple communication protocols (e.g., SPI and ISO 7816-3). The same physical contacts serve multiple protocol functions, and the system can adaptively select which protocol to use based on the operational state and requirements, thereby achieving universality that reduces the need for separate dedicated contacts for each protocol.
Solution Approach 2:
The contact assignment and protocol selection are made dynamic rather than static. The system can dynamically switch between different contact assignments and protocol modes depending on which protocol is being used. This dynamic configuration allows the same hardware to efficiently support multiple protocols without requiring permanent dedicated contacts for each, thus reducing overall device complexity while maintaining adaptability.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The present invention discloses a method, a terminal, a portable data carrier such as a chip card, and a corresponding system for selecting at least one communications protocol for communication between at least two communications subscribers, e.g. terminal and data carrier. In the method, a first communications subscriber, e.g. terminal, transmits a first request using a first communications protocol, e.g. Serial Peripheral Interface SPI, to a second communications subscriber, e.g. portable data carrier, in order to agree therewith on the first communications protocol for a subsequent communication. In reply to the first request, the second communications subscriber sends a response as a sign of agreement on the first communications protocol if it is using the first communications protocol, in which case the first communications protocol is then used for a subsequent communication between the communications subscribers. Otherwise a second communications protocol, e.g. ISO 7816, is agreed for a subsequent communication. The method is characterised in that the first request, using the first communications protocol, takes place during a period of time in which the second communications protocol is in an undefined state.