Firewire Bus Question

I have a late 2007 MBP 2.6 GHz which has both Firewire 800 and Firewire 400 ports. To the best of my knowledge this machine has only 1 Firewire bus and I'm assuming that the Firewire bus will run at the speed of the slowest device connected to it. If Any Firewire 400 devices are connected the whole bus is running at 400, correct?
I have adapter cables that are FW400 on one end and FW800 on the other. Both my computer and my only FW800 device have both kinds of ports on them. Does it matter which ports on the device and computer are used to connect this external drive? In other words is the FW400 port somehow constrained to 400 speeds?

Kappy wrote:
If you chain a FW400 device to a FW800 device connected to the FW800 port, then the port runs at the speed of the slower device. If you connect a FW400 device to the FW400 port and a FW800 device to the FW800 port then both devices run at their respective full speeds. Obviously if you connect a FW800 device to the FW400 port it will run at FW400 speed.
While that might be the way it seems to work, it's not what's specified in the 1394 standard, which defines the behavior of such 'bilingual setups'. This is an area where Firewire differs from USB. The designers of Firewire intended for devices in mixed setups to each operate at their highest speeds.

Similar Messages

FireWire Bus Power - How Much Power?

Is there any way to find out how many watts the FireWire bus power is on a Mac?
I have one of these:
http://www.wiebetech.com/products/ultragbplus.php
It's an external bus powered FireWire 800 drive. I have the 500GB version. It runs flawlessly on bus power on my PowerBook G4 17" using the FW 800 cable, and even runs fine on bus power when I try the FW400-to-FW800 cable.
On my Intel iMac Core Duo 20" though, it wil not run on bus power using the very same 400-to-800 cable so I guess the bus power on the iMac has... eh... less power.
It works fine on an iMac G5 using 400-to-800 but on the Intel iMac I have to attach the optional power supply to use it.
QUESTION: Has the bus power on the MacBook Pro changed too, is it lower than on the PowerBook G4???
This IS a strange one...
Intel iMac 2gHz/500/2GB/20" Mac OS X (10.4.6)

According to a FireWire white paper distributed by WiebeTech, FireWire ports usually provide 6-15 watts. A 3,5-inch drive needs 8.
My Intel iMac is not damaged. Any 2,5-inch bus powered drive works flawlessly. I tried this 500GB drive on three iMac G5 machines, works on bus power on all of them. Tried two different PowerBook G4s and it works on bus power on them too. I have now tried three different Intel iMac Core Duo machines and it does not work on any of them so obviously Apple has lowered the FireWire bus power output to just below what this drive needs.
I sent an email to WiebeTech who confirms this as a "known issue" and they don't know how the drive works with the MacBook Pro.... YET.
I guess I will have to try it out, just have to find an MBP

Unkown Device Showing up on Firewire Bus when nothing is connected

I have a brand new G5 dual 2.3 Ghz PowerPC not INTEL pci-e and when I go to the System Profiler and look under the Firewire Bus page it's indicating that I have an Unknown Device connected when in fact I don't have anyting externally connected. I do have two Digidesign PCI-E Audio cards installed but I can't see how this would be considered a firewire device. Anyone else have this problem or ideas on this? Thanks!

Glad to be of service.
Why reward points?(Quoted from Discussions Terms of Use.)
The reward system helps to increase community participation. When a community member gives you (or another member) a reward for providing helpful advice or a solution to their question, your accumulated points will increase your status level within the community.
Members may reward you with 5 points if they deem that your reply is helpful and 10 points if you post a solution to their issue. Likewise, when you mark a reply as Helpful or Solved in your own created topic, you will be awarding the respondent with the same point values.

Firewire & bus powered devices - Phonic FireFly 302 Plus

Hello Appleheads,
Looking for some help if you have a spare moment.
I just purchased a Phonic Firefly 302 Plus audio interface, and even though it is supposed to be able to be powered by the firewire bus, I am unable to get it to work. The unit's power light does not come on at all, however when using the external power supply that is also supplied it does work. I have tested two firewire cables, 1 of which I know works.
Are there any tricks to get this to work? Can you change power output settings for firewire ports somewhere in the system?
I am using a 6 circuit firewire 400 cable that came with the device. This is the only firewire device connected to my computer. The computer is connected to a power supply. Running OSX 10.6.4.
My Macbook Pro...
Model Identifier: MacBookPro4,1
Processor Name: Intel Core 2 Duo
Processor Speed: 2.4 GHz
Thanks for any help that anyone can provide.
Hartz.

The unit works fine with DC power. I am yet to test it on another computer to know for sure.
An interesting point has been raised to me though that has been discussed here: https://www.mhsecure.com/faq/index.php?action=artikel&cat=3&id=21&artlang=en&hig hlight=bus power
+The MacBook Pro models include protection circuitry to shut down the bus power when a device's inrush current amount violates a threshold. This issue affects the startup transient only, so you can power the MIO from its power supply to boot the box, then connect the FW to the computer, and remove the MIO power supply after it has joined the bus.+
Surely this threshold would be set to the maximum voltage provided on the bus? 12v?
Either way I have decided that I will just use the DC adapter.

Is there a way to manually reset firewire bus(ses)

I'm running Logic Studio (9) through an mLan Presonus Firestation and Yamaha Motif Rack XS. I have an addition al firewire card installed attached to a Focusrite Liquid Mix. The system is stable but isn't so flexible. If I change sample rates by mistake or change devices in the wrong order, the mLan system loses sync with the computer. The ONLy way to get the sync back is to close all of my audio programs and REBOOT the mac. This of course disturbs my workflow. Is there a way to reset the firewire bus(ses) through a software option without rebooting ?

I am having this same issue now but on a desktop. I have Tiger on one hard drive and Leopard on the other. I did a resetting of the NVRAM and I got my external firewire drives back - in Tiger. However when I restart up in Leopard 10.5.8 the drives will not mount, they show up in profiler so I know they are there but Leopard does not like firewire on my mirror door dual 1.25, but they all worked until a few days ago. This is my office computer where I do my student grading and other organizing, so I need my externals. Should I dump Leopard as I think I should and just go back to using just Tiger?

Is it possible to install a firewire bus in a new (2010) unibody macbook?

Hi,
I have been offered a good deal on a firewire audio interface but unfortunately my macbook doesnt have any firewire ports. I have tried it out using a firewire/USB adapter with a powered USB hub but the macbook just disables the port saying it is drawing too much power. Is there any way i can install a firewire bus in my macbook? or is there some kind of adapter/cable that would solve the power problem?
Thanks

No.

Overloading the Firewire Bus?

I am having troubles with having a Canon GL2 video camera being plugged into my iMac G5 via Firewire and a LaCie 250 GB external harddrive being plugged into my iMac G5 via Firewire at the same time. If they are both plugged in via Firewire at the same time, my iMac either a) freezes up thinking, b) doesn't detect my Canon, or c) doesn't detect my LaCie. I spent many hours speaking to Applecare and LaCie tech support and the only sound reponse I got (which was from LaCie) was that I was overloading my Firewire bus. Is this truly what's wrong? If it isn't give me your input and how to solve this thorn in my side, and if it is, tell me how can I transfer video smoothly from my Canon to my LaCie through some other means.
Thanks in advance.

Have you been able to transfer Canon to internal drive directly, or are you trying to send it through software to the FW drive indirectly with some form of compression etc. Also have a look at any La Cie software possibly installed and disable it. You dont need it to run a FW drive generally speaking and it may have interfering preference settings. My thoughts only, cheers.

ISight -missing FireWire Bus

My external iSight camera will no longer work on my G4 iMac after upgrading to iLife 08. It works on my Powerbook G4 laptop so there isn't a problem with the UBS cable. I have compared System Profiler details on both laptop and iMac. On laptop FireWire- Firewire Device Tree- FireWire Bus shows iSight.
On the iMac under FireWire there are no entries under FireWire Bus. Any suggestions

Turn off and unplug from the power socket the iMac and leave for 20mins to reset the firewire ports.

FireWire 800 questions

I have a few FireWire 800 questions:
Do all FireWire 800 connections use a 9-pin connector cable? Can the FireWire 800 with 9-pin connector also be used to power devices just like with a FireWire 400 port using a 6-pin connector? And lastly, what type of devices are generally used with a FireWire 800 port?

As far as I know yes.
You can get Firewire cables with changeable ends so that you can use the same cable 3 ways: 6 pin to 6 pin, 4 pin to 4 pin, and 4 pin to 6 pin. But never seen any that changes any of the above to 9 pin.
I have a Maxtor 300GB external HD that uses Firewire 800. It is just a bit faster and nowadays with the express cards even if you have the 15" MBP you still can use this option as opposed to FW400.
Hope this helps

Firewire Bus Power - Not Needed

I've been using an Echo AudioFire 12 firewire interface for years with my Mac Pro, but now I'm using it in the field with my MacBook.
The AF 12 is (AC) self powered yet the MacBook automatically sends it bus power, thusly running hotter and the fan never stops.
If I plug in a 6 pin FW cable to the MacBook and leave the other end un-attached the fan never turns on. When I plug in the AF 12, the fan starts up (within a few minutes).
Or is there a way to disable Firewire bus power on the Mac (10.6.5). Or can this be achieved using a cable that doesn't send power.
Any suggestions?
Thanks!

I had the same idea as you.
I didn't think of looking for a method of turning off the Mac's firewire power - this would be excellent.
The method I used was:
A firewire 6pin to 4pin cable like this (not this actual ebay item).
http://cgi.ebay.co.uk/2M-Firewire-IEEE1394-Cable-4-6-Pin-DV-out-PC-Lead-/2605482 48174?pt=UKComputing_CablesConnectors_RL&hash=item3ca9e2c26e#ht_2727wt1141
A firewire Adapter 6 Pin Male to *4 Pin Female* (not this actual ebay item).
http://cgi.ebay.co.uk/1394-Firewire-Adapter-6-Pin-Male-4-Pin-Female-/35040349329 7?pt=UKComputing_CablesConnectors_RL&hash=item5195acfdb1#ht_3761wt1141
My idea was that a firewire 4pin connection does not carry power, so the firewire signal would get through, but the power from the computer wouldn't.
The combined 6pin plug and adapter were heavy. They needed to be supported to keep them level when plugged in, if the socket was horizontally aligned, like on the MacBook Pro.
If you try this - be careful when ordering the adapter - some adapters are male to male - you need 6 Pin Male to *4 Pin Female*.
I also wrapped a piece of tape around the combined plug and adapter.
Hope this helps.
Richard

Firewire Bus Power - Un-needed

I've been using an Echo AudioFire 12 firewire interface for years with my Mac Pro, but now I'm using it in the field with my MacBook.
The AF 12 is (AC) self powered yet the MacBook automatically sends it bus power, thusly running hotter and the fan never stops.
If I plug in a 6 pin FW cable to the MacBook and leave the other end un-attached the fan never turns on. When I plug in the AF 12, the fan starts up (within a few minutes).
Or is there a way to disable Firewire bus power on the Mac (10.6.5). Or can this be achieved using a cable that doesn't send power.
Any suggestions?
Thanks!

Someone may know of a way to disable power on the macbook side of things, but I don't know how. I do know that if you use a 4-wire FireWire 400 cable it will not send power, and that they do make 6-pin cables that don't have power pins connected. It looks like the AudioFire 12 does not have a 4-pin FireWire port, but you may have some luck with a 6-pin cable that doesn't have power pins. This may not fix the issue, however, as depending on how many system resources are consumed by the AF 12, it may just be using enough CPU cycles or taxing the FireWire interface enough to kick the fan into high gear.

High pitch whine and FireWire bus power

Delighted with my MBP!
Just noticed the high pitch whine today when I set it up in a quieter room and plugged it into an IOGear bus-powered FireWire hub shared with my other Mac.
It was around 8000 hz and loud enough that I could not stand to stay in the room with it.
When I unplugged it from the hub and connected the cable directly to the FW port, the whine was greatly attenuated (I could hear it only by putting my ear next to the vents at the top of the keyboard).
Could the problem be related to powering the FireWire bus? (It reminds me of the sound of a switching power supply or DC-DC converter) Has anyone else had any success in finding ways to attenuate this high pitch tone?
MacBookPro Mac OS X (10.4.5) 7200 rpm

Hi, Thanks for the suggestion. I'm really trying to cut down on the number of devices that I leave plugged into the mains, so would ideally like a solution that relies purely on power supplied by the internal bus.
I've had a bit of progress with my current set-up. I've switched to using a 2 headed USB lead that came with my Hard Drive. This does mean I effectively lose a USB socket, but it appears that the Hard Drive + the Webcam can now live happily together.
It just means that I have to swap the 4th USB port for whatever ad-hoc device I need to use at the time rather than leaving things connected to it.
Out of geeky curiosity, I'd still be interested to know whether the USB and Firewire buses share their power or each have a dedicated amount.
Cheers,
Ian

FireWire Bus: Warning: Unable to list FireWire devices.

How do I fix this on my older G5
FireWire Bus:
Warning: Unable to list FireWire devices.
Trying to use my sony DCR HC-30
Use to work

Hi try this...
reset FW bus, same goes for USB reset...
Reset the Firewire bus
If your Firewire or USB isn't recognizing any device. A solution which has worked for some whose hard drive became invisible in 10.4 was simply to follow these four steps to reset the Firewire/USB bus:
1. Shut the machine down.
2. UNPLUG the power lead to the computer and any firewire/USB drive or devices.
3. leave it for 10 minutes.
4. Connect back up and reboot.
http://www.macmaps.com/firewirebug2.html

FireWire bus not responding

Subject says it all. At boot-up this morning, none of the FireWire devices are found. System profiler sees nothing on the FireWire Bus. Shutting down, rebooting, unplugging, plugging, powering down, powering up, all have no effect.

Thought you could use this info about getting FireWire to work!
First, you should always Repair Permissions in Disk Utility before and after any update; I would do that now. If you installed your update with FireWire plugged in, your Mac may not recognize it anymore.
Try resetting your FireWire ports by disconnecting all FW devices, shut down your Mac and unplug it from AC power (wall socket) for 30 minutes. plug it back in and try FW.
If that didn't work, download the combo update from this site (yours may be corrupt), not Software Update, disconnect all firewire + USB devices except keyboard + mouse, Repair Permissions, re-install update, Repair Permissions again + try. Yours is the 10.4.10 Combo update ( PPC, not for Intel systems). Others reading, download the Combo that applies to your system.
If that still didn't get it Zap the PRAM. While restarting Mac hold down the following key combo Command-Option-P-R. Keep holding those keys down till you hear the second start-up chime, then release.
For those of you with Macs that are not PowerBooks or iBooks, a bad internal battery can cause FireWire to not be recognized, so make sure it's good! Also, here is Apple doc.#88338 on getting FireWire to work.
Here's another
Fw Faq.
 Cheers! DALE

New Quad G5 - 'unknown device' on Firewire Bus

Even when nothing is connected to the Firewire ports, and after rebooting, System Profiler shows an 'unknown device' on the Firewire Bus. The Firewire bus works correctly, I've used it with hard drives and a Focusrite Saffire audio interface. The unknown device is always in the list.
Other Quad users seeing the same thing?

same thing for me, I think it's not something wrong.
Like there is hub integrated firwire hub...

Firewire Bus Question

Similar Messages

Maybe you are looking for