FireWire 400 Connector:
The 6-pin FireWire 400 technology supports serial
I/O at 100, 200, and 400 Mbps and provides
up to 7 watts of power when the computer system is on or
when the power adapter is connected and in sleep mode.
The FireWire 400 connector has six contacts, as shown in
Figure 3-2. The connector pin assignments are shown in
Table 3-2.
Figure 3-2 6-pin FireWire connector: 
| Table 3-2 Pin assignments on the 6-pin
FireWire connector |
| Pin |
Signal name |
Description |
| 1 |
Power |
Unregulated
DC - 12.8 VDC nominal |
| 2 |
Ground |
Ground return for power and inner cable shield |
| 3 |
TPB- |
Twisted-pair B, differential signals |
| 4 |
TPB+ |
Twisted-pair B, differential signals |
| 5 |
TPA- |
Twisted-pair A, differential signals |
| 6 |
TPA+ |
Twisted-pair A, differential signals |
| Shell |
— |
Outer cable shield |
When the computer is on or the power adapter
is connected, the power pin provides a maximum voltage of
12.8 V (no load) and 7 W power per port. Maximum output current
for both ports combined is 1.5 A and is controlled by a self-resetting
fuse.
Pin 2 of the 6-pin FireWire connector is ground for both
power and the inner cable shield. If a 4-pin connector is
used on the other end of the FireWire cable, its shell should
be connected to the wire from pin 2.
The signal pairs are crossed in the cable itself so that
pins 5 and 6 at one end of the cable connect with pins 3
and 4 at the other end. When transmitting, pins 3 and 4 carry
data and pins 5 and 6 carry clock; when receiving, the reverse
is true.
Information and Graphics Above - Copyright © 2007
Apple Inc. |
