Firewire Bus

IEEE 1394

[Firewire Description]
[Firewire ICs] [Firewire Standards]
[Firewire Connectors] [Firewire Pinout]


Firewire Description

Firewire [IEEE-1394] defines a media, topology and protocol for both a backplane physical layer or point-to-point serial cable interface. The interface is also called the High Performance Serial Bus (HPSB). On the Apple computer it became the high-performance replacement for the Apple Desktop Bus (ADB).

The backplane version uses two single ended signals and operates at 12.5Mbps [TTL], 25Mbps [TTL], or 50Mbits/sec [BTL or ECL].

The cable (differential) version operates at 100Mbps, 200Mbps, or 400Mbits/sec, [800Mbits/sec for 1394b] using half-duplex [full duplex 8B/10B encoding for 1394b].
Revision 'c' due out the first quarter of 2008 adds Gigabit Ethernet to the cable and increases the speed to 800Mbits/sec and 1600 Mbit/sec. Longer cable distance will also be increasing to 100m using UTP at S100, POF at S200 (S400), GOF at S3200. The pinout for Firewire is shown in a table below.

Devices on the bus are Hot-Swappable. It supports up to 63 devices at a maximum cable distance between devices of 4.5 meters. The maximum devices on the bus is 16 allowing a total maximum cable distance of 72 meters. Transmitting data over CAT5 cable allows data at 100Mbps to travel 100m [1394b]. Fiber cable will allow 100 meter distances at any speed [depends on the type of fiber cable].

The digital interface supports either asynchronous and isochronous data transfers. Addressing is used to a particular device on the bus. Each device determines its own address.
Note, beginning in 2008 Apple Computer was no longer providing Firewire on some of its Notebook computers. As of Nov 2009 Firewire is only found on three of the five MacBooks being offered. The smallest of the MacBooks do not offer Firewire, while the larger three units offer one FireWire 800 port. As of 2011 search traffic continues to decline to about half what it was in 2009.

{Firewire Bus Index}

Firewire Bus Interface IC Vendors


Fujitsu Microelectronics Inc.

Genesys logic company {USB 2.0 to IEEE-1284/DMA Bridge Controller/UTMI Compliant Transceiver, ATA/ATAPI Controller, Disk Controller}

NEC Corp.

NXP {IEEE1394 link layer controller/Physical layer interface ICs}

STMicroelectronics {IEEE1394}

TI {Link/Physical Layer Controller IC}

IC Manufacturers {All other types}

{Firewire [IEEE-1394] Bus Index}

Firewire Online Standards and Specifications

IEEE-STD-1394-1995: IEEE Standard for a High Performance Serial Bus
IEEE-STD-1394a-2000: IEEE Standard for a High Performance Serial Bus
IEEE-STD-1394b-2002: IEEE Standard for a High Performance Serial Bus

IEEE-STD-1394c-2008: IEEE Standard for a High Performance Serial Bus
IEEE1394c is the latest released standard.

Serial Bus Protocol 3: [SBP-3]; specifies a protocol for the transport of commands, data and status between devices

Also refer to; ANSI/SCTE 26 2004, Home Digital Network Interface Specification with Copy Protection

1394 Trade Association {}
IEEE {Institute of Electrical and Electronic Engineers}

I believe that the term Firewire is a trade mark, so search on IEEE-1394 for data.

{Firewire [IEEE-1394] Index}

Firewire Connector Manufacturers and Pin-out

6 to 4 pin Firewire connector Shapes
6 pin and 4 pin Firewire Connectors

Advanced-Connectek INC. 'ACON'
Amphenol {FireWire Plugs and Receptacles}
DDK Electronics, Inc
FCI {IEEE 1394 Connectors}
Foxconn {IEEE 1394 Type A, Type B, Combo Connectors}
ITT Cannon {USB Board: Horizontal SMT, Horizontal DIP, Upright DIP. USB Cable: Plug type}
Keystone {Plug and Socket IEEE1394 Connectors; Horizontal/Vertical Mounting Style, SMD/Thru-hole}
Kycon {IEEE1394 Surface Mount Connectors, Right Angle, Upright, PCB Mount, 4-pin}
Molex {IEEE 1394 Connectors and Cable Assemblies}
Switchcraft {Right angle PC and surface mount to 1394R-4006N}
Tyco Electronics

{Firewire [IEEE-1394] Index}

Firewire Connector Pinout

Two types of connectors are used with FireWire; 4 pin connector (consumer electronics), and a 6 pin connector (computers).
The 6 pin connector has the following pinout:
Pin 1; Power, 30 volts
Pin 2; Ground
Pins 3, 4; B Twisted pair (-/+)
Pins 5, 6; A Twisted pair (-/+)
Cable shield
Pins 3/4 are crossed with pins 5/6 at the opposite ends of the cable. The transmitter sends clock [Strobe] on 3/4, and data on 5/6.

6 to 4 pin Firewire [IEEE-1394] connector Pin-out
6 pin to 4 pin Firewire [IEEE-1394] interconnection and Firewire pin out
Signal names and pinout for the 6 and 4 pin connectors: [1394a-2000 added the 4 pin connector]

FireWire Pinout
Pin Number 6 Pin Connector 4 Pin Connector
5 TPA* (Shell) VG
6 TPA -
TPA is Transmit Strobe, Receive Data
TPB is Receive Strobe, Transmit Data

9 Pin Connector FireWire Pinout
Pin # Signal Name Pin Function
1 TPB* Twisted Pair B, Minus
2 TPB Twisted Pair B, Plus
3 TPA* Twisted Pair A, Minus
4 TPA Twisted Pair A, Plus
5 TPA (R) Ground, Twisted Pair A
6 VG Power Ground
7 NC No Connection
8 VP Power Voltage
9 TPB (R) Ground, Twisted Pair B
Plug Shield Cable Shield Ground

Note the pin out table for the 4-Pin and 6-Pin connector is not an interconnection table, it just defines the pinout.
Use the schematic above to determine interconnection.

{FireWire Bus Index [IEEE-1394]}

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Modified 2/26/12
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