# what is the use of a IEEE-1394A Ports?



## vasulic (Aug 29, 2005)

Can anyone explain me the uses of IEEE-1394A Port?


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## AlienTech (Aug 29, 2005)

They are kind of like USB ports developed by Apple called firewire. All digital cameras have IEEE interfaces so you can transfer and edit as well as control the camera from your PC using this port. You can do frame editing as well as copying video to your PC without loss unlike a video capture device where you have to convert a video signal to digital and then store it. I think its great...

You can also use special programs to backup your system onto your camera  Right now the tapes cost a lot more than DVD's but store almost the same amount of data. But 3-4 years ago DVD's were much more expensive so they came in handy.

There are also hard drives which use this interface and it is faster than USB2. So to get 16X DVD writes you need to use IEEE instead of USB2 which maxes out around 12X.

But for me able to transfer video from my DV cam without dropping frames or loss of quality is the main benefit.
*videosystems.com/mag/video_firewire_transfer/


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## vasulic (Aug 29, 2005)

Thanks alien


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## siriusb (Aug 29, 2005)

> So to get 16X DVD writes you need to use IEEE instead of USB2 which maxes out around 12X.


Someone told me the same thing, but I've got a doubt.
See:
16x DVD is equal to 177.28 Mbps
and
USB 2.0 (Hi-speed usb) is 480Mbps

Now how do they (& you) say that usb2.0 don't have enuf bandwidth??


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## AlienTech (Aug 29, 2005)

siriusb said:
			
		

> > USB 2.0 (Hi-speed usb) is 480Mbps
> >
> > Now how do they (& you) say that usb2.0 don't have enuf bandwidth??
> 
> ...


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## AlienTech (Aug 29, 2005)

USB 2.0 vs. FireWire

Direct connection 
*www.ixbt.com/storage/usb-to-fw/w2k-direct.png
*www.ixbt.com/storage/usb-to-fw/w2k-direct.png

Via USB 2.0 
*www.ixbt.com/storage/usb-to-fw/w2kusb2.png
*www.ixbt.com/storage/usb-to-fw/w2kusb2.png

Via FireWire 
*www.ixbt.com/storage/usb-to-fw/w2k-fw.png
*www.ixbt.com/storage/usb-to-fw/w2k-fw.png

Connection Type: Direct --- USB 2.0 --- FireWire 
Transfer Begin: 41900 Bytes/Sec --- 14200 Bytes/Sec --- 36100 Bytes/Sec
Transfer End: 25600 Bytes/Sec --- 14200 Bytes/Sec --- 25500 Bytes/Sec

*www.digit-life.com/articles/usb20vsfirewire/

You can see that the IEEE transfer rate hits its max 40MB/sec while the USB2 implementaion is rather slow.
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## siriusb (Aug 29, 2005)

Er..um..nice. So, u mean to say that usb2 implementations don't follow the usb2 specification? If that's not what u mean, then I still don't get why usb2 with 480Mbps shud be slower than 1394a supporting only 400Mbps.


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## Keith Sebastian (Aug 29, 2005)

siriusb said:
			
		

> 16x DVD is equal to 177.28 Mbps
> and
> USB 2.0 (Hi-speed usb) is 480Mbps
> 
> Now how do they (& you) say that usb2.0 don't have enuf bandwidth??



USB 2.0 does not achieve 480Mbps in real world operating conditions. Quote from an article at tomshardware.com
USB 2.0 was developed to provide more flexibility for USB, especially for applications such as mass storage. All PC systems available today support USB 2.0, which increases bandwidth from 12 Mbit/s all the way to 480 MBit/s, or 60 MB/s. *Real-world throughput is usually only just under 30 MB/s, but this is still more than enough for most newer external devices.*

*www.tomshardware.com/storage/20050114/external-hds-01.html

Keith


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## AlienTech (Aug 29, 2005)

siriusb said:
			
		

> Er..um..nice. So, u mean to say that usb2 implementations don't follow the usb2 specification? If that's not what u mean, then I still don't get why usb2 with 480Mbps shud be slower than 1394a supporting only 400Mbps.



Because of implementation. IEEE is designed to bus master without interruptions for continuous data transfers. But it still dont explain why it is much faster. So I would think it has to do with cheap and bad chip sets. I have USB2 external cases where 2 of them wont work faster than 15MB/sec while another 2 using a different chip set does 25MB/sec on the same hard disk. Anyone making such bad stuff for IEEE will immediately get returns because when they go home and hook up their DV type stuff to it you dont want your expensive video camera to sit there doing frame by frame video transfers and then rewinding to a frame it missed...  Thats what amazed me about IEEE, I can transfer and capture in real time the video and it takes 60 minutes for an hour's video from the tape. It has never skipped... Even on a 500MHZ P3. Of course you cant do anything else and the computer appears to lock up. But it works.


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## anispace (Aug 31, 2005)

Can some1 tell me how to capture pure video+audio from my DV cam(SONY DCR HC-40). The software provided with it captures video with some mp3 music mixed with it(which i do not want).

Also it takes upto 2hrs. in usb2.0. My DV cam supports Firewire but the cable isnt provided.So where can i get the cable.


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