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KB 1858

FireWire connection problems: Tethering a Digital Back to laptops, iMacs and other underpowered computers

Last updated: 11-04-2018


I am having connection problems. What is the recommended configuration when shooting tethered to a laptop computer?


  1. If you have a computer with USB-C ports only (like the current MacBook Pro): see KB Article #1843
  2. If you have a computer with no Firewire port but a Thunderbolt 1 or 2 port: See KB Article #1256
  3. If you have a computer with a Firewire port:  See below: 


Force battery mode or use powered firewire hub.

  • Portable and iMac computers from Apple do not provide sufficient power to Phase One and Leaf Digital Backs from the FW bus *
  • Most portable computers that run Windows do not provide any power from the FW bus*


Below are suggested configurations when shooting to a portable computer such as a PC or Apple laptop and iMac's. This solution should be used for some specific desktop Apple computers such as iMac or Mac Mini. These computers do not provide enough power through their firewire ports to completely support the digital back in tethered mode.

H-series backs:
A powered firewire repeater is required.  Please see below for recommendations.


P20, P25:
The back is not able to use battery power when tethered to a computer unless you follow the instructions listed below.  Connect either the "No Power Firewire Cable (Item No. 70508)" solution or the Capture Integration FireWire Port Isolator
This forces the back to use battery power.



You can also use a powered firewire repeater.

P45, P30, P21, and All P+ backs
Set the unit to "force battery mode". This refers to a situation when the back will be forced to use battery as its primary source of power even though it is connected to a computer via firewire cable. To activate this mode, please access "Menu" on the digital back and select > "Configuration" > "Power Source" > "Battery" > Choose "Green Check".


IQ1xx, IQ2xx, and Mamiya Leaf Credo
These backs require and will only draw power from the battery so no additional hubs are required.  If connecting directly to a portable computer battery charging should be set to Off in Power Management.


If you want to charge the battery as well, connet via a powered firewire repeater.

Aptus, Aptus S, and Aptus II
Aptus backs cannot use battery while tethering so all power must come form the firewire cable.  To provide enough power to run the back you must connect via a powered repeater.


What Firewire Repeaters are recommended?



Unibrain FireRepeater-800 Pro 5 port
Lindy 3 port Firewire 800 repeater
Firewire 800 Hub repeater - 4port

With all repeaters is is critical that you use a capable power supply.  Recommend DC 12V, 1.25 - 3A


What is the Power kit for PowerPhase FX (Item No. 70506)?


Repeater & AC adapter. Can be used as a substitute for the battery in the portable solution.
If you want to use the portable solution with an AC power supply please order the power kit.

Please Contact your Phase One Dealer to order these components.