BY MATT VINCENT
The 1394 Trade Association (www.1394ta.org), which supports and enhances technology based on the IEEE’s 1394 FireWire specifications, recently formed a task group to complete the IDB-1394 copper specifications for use of copper in 1394-based vehicle entertainment networks.
The group said it will work with the IDB-1394 copper backbone document, which outlines basic requirements for audio and video transmission over copper, including 400-Mbit/sec bandwidth and the availability to move audio/video signals through vehicle networks that can reach 4.5 meters.
Working under the direction of the Automotive Working Group, the group also will interact with the Silicon Working Group and the Compliance and Interoperability Working Group, to concur on the scope of the specification and ensure that it will be consistent with the requirements of automobile manufacturers and their OEM suppliers.
The pending specification will cover the requirements for shielded twisted-pair, twisted quad, and coaxial. It also will support the power-budget criteria so automobile manufacturers and their suppliers can implement cable lengths sufficient to deal with vehicle harness layout constraints and complexities.
“There are advantages and disadvantages with both copper and plastic optical fiber,’ says Ricardo Wong, assistant manager for multimedia planning at Nissan Corporation’s Advanced Engineering Center. Wong also is a member of the 1394 Trade Association. “It is in everyone’s interest to complete the copper specification, so we enable the automakers and their OEM suppliers to have as many options as possible for both the backbone and for individual controller modules within the network.”
Coax task group also at work
According to the association, major automakers from the United States, Europe, and Japan are implementing initial in-vehicle multimedia networks, with many manufacturers moving toward the use of IDB-1394-based technology.
The 1394 group also recently announced that it has established a new task group to develop an IEEE 1394 baseband-over-coaxial cable PMD specification for use across a wide range of automotive, residential, and industrial networking applications.
The task group will work under the auspices of the 1394 Trade Association’s Silicon Working Group, with support from the group’s Automotive Working Group. It will be chaired by Les Baxter, a veteran member of the Trade Association, founder of Baxter Enterprises, and chair of the IEEE P1394r committee that is updating and revising the entire suite of IEEE 1394 standards.
A prototype of this technology has been demonstrated by Eqcologic NV, a 1394 Trade Association member company.
Baxter says the task group will create two documents: a requirements document and the PMD specification, which will include power options as well as the electrical transmission specification. Proposed performance will be bidirectional at data rates of 800 Mbits/sec over 18 meters of coax with up to five inline connectors. Development of the 1394 baseband over coax specification will complement the coax bridge and UTP PMD specifications already developed by the 1394 Trade Association.
Baxter says, “The baseband coax PMD will be a simple, low-cost interface that will provide high throughput in harsh EMC environments while using economical coaxial cables and standard connectors. The baseband coax interface also will have the potential to support higher data rates and/or longer distances.”
According to the Trade Association, the IEEE 1394 standard is an optimal method for delivering high quality audio and video, because the bandwidth required for A/V streaming is guaranteed, and because 1394 uses a reference clock to maintain optimal A/V signal synchronization.
