ISO 1745
ISO 1745, titled "Information Processing Systems — Character Structure for Start/Stop and Synchronous Transmission," defines a basic framework for communication between devices using character-based protocols. It provides specifications for character encoding, message formatting, and transmission control, ensuring compatibility and reliability across systems that utilize synchronous or start/stop transmission methods.Key Aspects of ISO 1745:
- ''Character Encoding and Structure'' ISO 1745 specifies how characters are encoded for data transmission. The character structure is typically designed to support 7-bit or 8-bit character sets, allowing compatibility with widely used encoding standards. Each character is sent with start and stop bits for asynchronous communication or with strict timing for synchronous protocols.
- ''Message Formatting'' The standard outlines how messages should be structured for consistent transmission. A typical message includes a start delimiter, data fields, and an end delimiter. This format ensures that receiving systems can correctly interpret where a message begins and ends, preventing errors caused by misaligned data streams.
- ''Transmission Control Mechanisms'' To ensure robust communication, ISO 1745 defines control characters and sequences used for flow control and error detection. Examples include characters for indicating the start of a message, acknowledgment of receipt, or requesting retransmission in case of errors. This enhances data integrity and ensures synchronized communication.
- ''Compatibility with Start/Stop and Synchronous Systems'' The standard accommodates both asynchronous (start/stop) and synchronous transmission. Asynchronous systems send data character by character, using start and stop bits for timing, while synchronous systems send data in a continuous stream, relying on an external clock signal for synchronization.
- ''Applications and Interoperability'' ISO 1745 provides a foundation for various communication protocols used in telecommunications, industrial systems, and data processing. Its simplicity and adaptability make it suitable for systems that require basic yet reliable communication, ensuring interoperability between devices from different manufacturers.
This standard represents a key step in creating universal communication guidelines, streamlining data exchange in early and modern computing systems.