What Color Is The Ieee 1394 Cable End IEEE 1394 Serial Bus – Firewire The IEEE 1394-1995 standard, commonly referred to as 1394, outlines a high-performance serial bus technology and interconnection system that delivers services similar to contemporary parallel buses but at significantly reduced costs. While 1394 encompasses advanced technology, it is the cost-effectiveness that led to its adoption in the digital video and audio consumer markets starting in 1997. This technology’s capabilities are well-suited to support various high-end digital audio/video applications, including consumer audio/video device control, signal routing, home networking, nonlinear digital video (DV) editing, and 32-channel (or more) digital audio mixing. Sony’s DCR-VX700 and DCR-VX1000 DV camcorders, launched in September 1995, were among the pioneering products to incorporate 1394. Subsequently, Sony introduced its DCR-PC7 micro-DV camcorder in late 1996, and Matsushita announced the availability of the Panasonic NV-DE3 DV camcorder with a 1394 connector in early 1997.
Features of IEEE-1394
IEEE-1394 offers several features:
- Real-time Data Transfer for Multimedia Applications: It provides real-time data transfer capabilities suitable for multimedia applications.
- Data Rates: IEEE-1394 supports data rates of 100 and 200 Mbits/s, with an upgrade path to 400-800 Mbits/s and even multi-Gbits/s.
- Live Connection/Disconnection: Devices can be connected or disconnected without data loss or interruption.
- Automatic Configuration (Plug and Play): IEEE-1394 supports automatic configuration, making it a plug-and-play technology.
- Freeform Network Topology: It allows flexible network topologies, including mixing branches and daisy-chains.
- No Separate Line Terminators Required: Unlike some other bus systems, IEEE-1394 doesn’t require separate line terminators.
- Guaranteed Bandwidth Assignments: It offers guaranteed bandwidth allocations for real-time applications.
- Common Connectors: Devices from different manufacturers and for various applications can use common connectors.
The IEEE-1394 standard defines two bus categories: backplane and cable. The cable bus, the focus of this discussion, is a “non-cyclic network with finite branches,” consisting of bus bridges and nodes (cable devices). Non-cyclic means that devices cannot be connected in loops. It supports up to 64K nodes with 16-bit addressing and allows up to 16 cable hops between nodes. Bus bridges connect different types of busses or a cable bus with a backplane bus. Node IDs and bus IDs are used for addressing nodes and bridges, accommodating various configurations.
Each node typically has three connectors, allowing up to 16 nodes to be daisy-chained with standard cables up to 4.5 meters long, totaling a standard cable length of 72 meters (higher-quality cables permit longer interconnections). Physical addresses are assigned during bus reset or when nodes are added or removed. Devices can be hot-plugged, and no device ID switches are required.
Physical Layer, Link Layer, and Transaction Layer
The 1394 protocol operates through three stacked layers:
- Transaction Layer: Implements a request-response protocol conforming to the ISO/IEC 13213:1994 standard Control and Status Register (CSR) Architecture for Microcomputer Buses.
- Link Layer: Provides an acknowledged datagram to the transaction layer, handles packet transmission and reception, and manages cycle control for isochronous channels.
- Physical Layer: Handles initialization, arbitration, and translation of the serial bus data stream and signal levels. It may include galvanic isolation to prevent ground loops when required.
Cables and Connectors
Standard bus connections are made using 6-conductor cables containing two separately-shielded twisted pair transmission lines, two power conductors, and an overall shield. The twisted pairs are crossed in each cable assembly for transmit-receive connections. Power conductors supply up to 40 volts at 1.5 amps max to the physical layer in isolated devices. Connectors are derived from the GameBoy design and use either friction detent or side-locking tab restraints for secure connections.
IEEE-1394 Bus Management
IEEE-1394 offers flexible bus management, including a cycle master, isochronous resource manager, and optional bus master. On bus reset, the bus structure is determined, node IDs are assigned, and arbitration for cycle master, isochronous resource manager, and bus master nodes occurs. Bandwidth allocation is based on unit measurements in bandwidth allocation units, and bandwidth requests can be repeated periodically if sufficient bandwidth is not initially available.
Consumer Electronics Applications for 1394
IEEE-1394 is ideal for various consumer electronics applications, including digital camcorders, DVCRs, digital videoconferencing systems, musical synthesizers, printers, PC disk drives, PC networking, cable TV set-top boxes, digital video disk (DVD) drives, and more. Its ability to operate without a bus manager makes it suitable for connecting devices directly without the need for a PC or controller.
Please note that some specific products and applications have been mentioned for context and illustration in the IEEE-1394 ecosystem.