Differences to consider when selecting an IEEE-1394 (FireWire) host adapter card

Last Revision Date: 10/21/2015

This article describes some of the differences to consider when purchasing an IEEE-1394 (FireWire) host adapter card. 

Some of these differences can be attributed to the type of FireWire Open Host Controller Interface (OHCI) (or chipset) used by the card. Common chipsets include: LSI/Lucent/Agere, Texas Instruments (TI) and VIA.

MAXIMUM NUMBER OF DMA CHANNELS
The number of simultaneous DMA channels (also known as isochronous transmit / receive contexts) supported by the card determines the number of FireWire cameras that can stream images at the same time. Although the 1394 standard limits the maximum number of simultaneous isochronous channels to 32, there is currently no host adapter that is capable of supporting 32 channels.

FIFO BUFFER SIZE
The size of the on-chip isochronous and asynchronous receive and transmit FIFOs for the FireWire packets can affect streaming performance. Larger FIFOs generally result in better recovery from PCIe bandwidth issues.

SUPPLYING POWER WITH FIREWIRE CABLE
Most on-board host adapter cards for laptops and some PCIe cards for desktop systems are built for use with a 4-pin FireWire cable. These require a 6-pin connector (the additional two pins provide power). Some FireWire accessory manufacturers sell cables that have one 4-pin end and one 6-pin end. However, the cameras still require power to be provided. See "My laptop’s IEEE-1394 port or PCMCIA card doesn't supply power to my camera for more details."

IEEE-1394b SUPPORT
Most FireWire card manufacturers offer 1394b host adapters. 1394b is a significant enhancement to the basic 1394 specification, and is fully backwards compatible with the 1394-1995 and 1394a specifications. "Using IEEE_1394a cameras with 1394b Open host controller interface cards" explains some of the issues when using an IEEE 1394a camera on a 1394b host adaptor.

WHICH CARD SHOULD I BUY?
We sell FireWire PCle cards and have had positive experiences with cards based on the LSI/Lucent/Agere and Texas Instrument chipsets. Aside from the trade-offs listed above, there are no significant performance variations, particularly between cards based on the same chipset. Some vendor products which we have shipped with our cameras are listed in "Where can I buy FireWire/IEEE-1394 and digital camera accessories?"

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