How do I network the PowerBook G4 to another Mac?

There are several ways to network the PowerBook G4 to another Mac.

Wirelessly (AirPort/AirPort Extreme)

Two AirPort (802.11b) or AirPort Extreme (802.11g) equipped PowerBook G4 models or one wireless capable PowerBook G4 and another AirPort or AirPort Extreme-equipped Mac, can be networked together without the AirPort hardware access point by using "direct computer-to-computer communications" within a range of approximately 50 meters.

For Macs that have 10Base-T or 10/100Base-T or faster Ethernet installed and are capable of running MacOS 8.6 or higher, the first Mac can be added to an AirPort network via a crossover Ethernet cable between the computer and the hardware access point and the PowerBook G4 can be added to the same network by the wireless connection if AirPort or AirPort Extreme is installed.

Wired (Ethernet)

If you're not interested in using wireless networking, or your PowerBook G4 does not have AirPort or AirPort Extreme installed, two Gigabit capable PowerBook G4 notebooks -- all but the PowerBook G4/400 (Original - Ti) and G4/500 (Original - Ti) -- or one Gigabit capable PowerBook G4 notebook and a another Mac that has Gigabit Ethernet installed can be connected with a "standard four pair category 5 or better Ethernet cable".

Gigabit equipped PowerBook G4 models have a "cable-sensing Ethernet port" to determine whether you have connected the computer to an Ethernet hub or another computer, and respond accordingly.

To connect a non-Gigabit equipped PowerBook G4 system -- the PowerBook G4/400 (Original - Ti) or G4/500 (Original - Ti) -- to another older system without Gigabit Ethernet, you generally can just use a simple crossover cable, or Ethernet cables and a hub, to connect another Mac to the PowerBook. Although it has not been updated in quite some time, Three Macs & A Printer covers basic types of wired networking in-depth.

Firewire

The PowerBook G4 can also be connected to another FireWire-equipped Mac, by using "FireWire Target Disk Mode". In this mode, the other computer simply will appear as a second hard drive on the desktop of the PowerBook. According to Apple "to use Target Disk Mode, simply connect the computers using a FireWire cable, then start the second computer while holding down the 'T' key on its keyboard."

For additional information, please refer to "How to Use Firewire Target Disk Mode".