Apple 17-INCH manual FireWire 800 Connector, Pin Signal name Description

CHAPTER 3

Devices and Ports

Figure 3-26-pin FireWire connector

Table 3-2		Pin assignments on the 6-pin FireWire connector
Pin	Signal name		Description
1	Power		Unregulated DC; 12.8 V
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.

FireWire 800 Connector

The FireWire 800 port on the PowerBook G4 17-inch computer is based on IEEE 1394b and enables a 800 Mbps transfer rate. FireWire 800 uses a 9-pin connector and is backwards compatible with original 1394 FireWire devices with 6-pin or 4-pin connectors. With the appropriate cable, the new 9-pin port works seamlessly with legacy FireWire devices. Cables are available to go from both 6-pin and 4-pin connectors to a 9-pin, and 9-pin to 9-pin.

FireWire Ports 27

Legacy Document 2003-03-01 © 2003 Apple Computer, Inc. All Rights Reserved.