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1394 joins the backbone battle

Nov 12, 20033 mins
Cellular NetworksNetwork SecurityWi-Fi

* New version of the high-speed video bus shows great promise for home networks

While it’s clear that Ethernet and Wi-Fi will dominate home networks for years to come, what we’ll be using for the backbone – to carry video from point to point – isn’t. Several technologies might fit the bill, including coax cabling, HomePNA, HomePlug, and now, IEEE 1394.

Also known as Firewire, 1394 is a high-speed video connection that today is often used in digital video cameras to transfer large amounts of data quickly a short distance between it and a PC. However, there are a number of reasons why 1394 might proliferate in home networks. 

First, the new version, 1394b, allows for much longer distances at twice the speed – 100 meters at up to 800M bit/sec for the new version vs. 4 meters at 400M bit/sec for 1394a. That’s a lot faster than Ethernet and HomePNA 3.0, which top out at 100M bit/sec. The next-generation HomePlug spec, HomePlug AV, is expected to achieve 200M bit/sec, and the next generation of Wi-Fi about 150M bit/sec (All minus overhead, of course.)

Another advantage of 1394b is that the IEEE developed the specification to allow for travel over different types of wiring, including glass optical fiber and Cat 5 copper wiring. In other words, if you’ve already wired your home for Ethernet or bought a new home equipped with structured wiring, perhaps someday you’ll be able to send much faster 1394 signals over your existing infrastructure.

There is some early development of 1394b products for home networks. Texas Instruments recently launched a 1394b chip that it’s targeting to the 1394 home network market. The device is backward-compatible with 1394a gear, so you’ll be able to connect a 1394a-enabled PC into a bridge device and then send the signals to a 1394b device, such as a settop box, for instance. Also important, TI’s 1394b device will work with Cat 5 cabling, the first available device that allows for 1394b over Ethernet cabling.

TI has also designed a system design called OnRamp, a 1394b home network bridge, which it demonstrated at the CEDIA trade show in September. TI partnered with Digital Media Group to develop the system, which the latter calls a “1394b Audio/Video Hub.” A company called Digital Home Technologies, which designs home network systems, is using OnRamp for its MediaNet media network gear. TI also says it’s working with some structured wiring vendors to sell 1394 wall plates, which would use 1394b for the backbone technology, then have the signal convert back to either Ethernet or 1394a at the device end. 

One last note: The IEEE has created a study group to investigate sending 1394b over existing Gigabit Ethernet physical layer connections. The specification would speak Gigabit Ethernet and 1394 protocols, allowing for chips that can send video signals over an Ethernet network while incorporating the quality of service inherent in 1394.