3 pin stereo plug connector at the power adapter cable (2.5mm jack used).
The Apple PowerBook G4 Titanium (TiBook) uses a proprietary 3-conductor barrel jack — described by Apple as a “mini-RCA-style jack” — for its DC-in (AC adapter) port. Electrically it is a 2.5 mm stereo-style tip/ring/sleeve plug carrying +24 V DC, ground, and a passive sense resistor line. The adapter delivers 24 V DC at either 45 W (1.875 A, model M8482/A1036) for early Gigabit Ethernet models or 65 W (2.65 A) for later variants. This connector carries only the DC power supply from the external adapter; the Smart Battery communication interface (SMBus SDA/SCL) resides on a separate internal multi-pin connector between the battery and the logic board.
| Pin | Name | Direction | Description |
|---|---|---|---|
| 1 | sense | 400KOhm to GND | |
| 2 | GND | Ground | |
| 3 | Vin | IN | +24V power |
Signals
- sense — passive sense resistor (~400 kΩ to GND); used by the adapter’s LED indicator circuit and prevents the outer sleeve from acting as a direct ground return. It carries no digital or SMBus signal.
- GND — ground return for the DC supply.
- Vin — +24 V DC input from the AC adapter; 45 W (early models) or 65 W (later DVI and 867 MHz/1 GHz models).
Notes
The DC-in port was soldered directly to the logic board on early TiBook models (Original and Gigabit Ethernet revisions, January 2001 – April 2002). From the DVI revision onward (April 2002) Apple introduced a separate, replaceable DC-in card. The connector accepts a 2.5 mm male jack — not the 3.5 mm size found on standard audio equipment. The sense line measures approximately 400 kΩ to GND and is not an SMBus or data connection; the Smart Battery Data protocol operates entirely on the internal battery connector.