Apple Desktop Bus (ADB)

• The mouse draws up to 10 milliamperes (mA).
• The keyboard draws 25-80 mA (varies with keyboard model used).
• The maximum current available for all ADB devices is 500 mA.

The ADB port can support up to three ADB devices.

Audio and Telecommunications Devices

The following table shows power allowances for external devices connected to input ports.

Device	Voltage	Current	Power
Microphone	+5 V	20 mA	100 mW
A device connected to the printer port or modem port	+5 V	500 mA	2.5 W

Expansion Cards and Internal Storage Devices

If you add an expansion card or a 3.5-inch storage device to your computer, make sure the component's power requirements don't exceed the maximum power allowances allocated to it by the computer.

The maximum power allowances for expansion cards in your computer can accommodate three 15-watt cards, two 25-watt cards, or one 15-watt card and one-25 watt card. Some detailed guidelines are presented in the following table.

Device	Voltage	Current	Power
Expansion card (15 watts) 1	+5 V	3 A	15 W
	+12 V	0.500 A	6 W
	-12 V	0.100 A	1.2 W
	+3.3 V	2 A	6.6 W
Expansion card (25 watts )2	+5 V	5 A	25 W
	+12 V	0.500 A	6 W
	-12 V	0.100 A	1.2 W
	+3.3 V	2 A	6.6 W
Storage devices (such as a hard disk)	+5 V	3 A	15 W
	+12 V	2.3 A	27.6 W
	+12 V	6.2 A peak 3
1 15-watt expansion cards should not consume more than 15 watts of total power. 2 25-watt expansion cards should not consume more than 25 watts of total power. 3 Peak power is for startup only and must not occur in normal operation.