TITLE
    Energy Saver Modes: Different Sleep Modes Explained
Article ID:
Created:
Modified: 		20181
7/18/96
4/17/00
TOPIC

    If I choose Sleep from the Special menu on my computer, it powers down my monitor and the monitor cools down. However, if I use the timed delay sleep mode in the Energy Saver control panel, the video signal disappears, but the monitor never cools. Why?

DISCUSSION

    There is a difference in the way the two sleep functions work. Choosing the Sleep mode from the Special menu puts the monitor into a low-power state, but using the Energy Saver software merely blanks the video with composite and vertical sync. still present.

    The Energy Saver Control Panel was designed this way so that you would not have to wait a long time for the display to warm up from a cold start if the Display sleep was set separately at under 30 minutes.

    Below is a table showing the video signals in the various modes.

    +=====+===========+=======================+=========+=========+==========+
    | Pin | Signal    |Description            | W/Video |  Sleep  |  Energy  |
    |     |           |                       |         |  Menu   |  Saver   |
    +=====+===========+=======================+=========+=========+==========+
    |  1  | RED.GND   | Red vid. ground       | GND     | GND     | GND      |
    +-----+-----------+-----------------------+---------+---------+----------+
    |  2  | RED.VID   | Red vid. signal       | Video   | No video| No video |
    +-----+-----------+-----------------------+---------+---------+----------+
    |  3  | /CSYNC    | Comp. sync. signal    | *Sync.  | No sync.| Sync.    |
    +-----+-----------+-----------------------+---------+---------+----------+
    |  4  | SENSE0    | Monitor sense 0       | --      | --      | --       |
    +-----+-----------+-----------------------+---------+---------+----------+
    |  5  | GRN.VID   | Green vid. signal     | Video   | No video| No video |
    +-----+-----------+-----------------------+---------+---------+----------+
    |  6  | GRN.GND   | Green vid. ground     | GND     | GND     | GND      |
    +-----+-----------+-----------------------+---------+---------+----------+
    |  7  | SENSE1    | Monitor sense 1       | --      | --      | --       |
    +-----+-----------+-----------------------+---------+---------+----------+
    |  8  | +12V      | 12-volt from computer | Sync.   | No sync.| No sync. |
    +-----+-----------+-----------------------+---------+---------+----------+
    |  9  | BLU.VID   | Blue vid. signal      | Video   | No video| No video |
    +-----+-----------+-----------------------+---------+---------+----------+
    | 10  | SENSE2    | Monitor sense 2       | --      | --      | --       |
    +-----+-----------+-----------------------+---------+---------+----------+
    | 11  | GND       | CSYNC & VSYNC ground  | GND     | GND     | GND      |
    +-----+-----------+-----------------------+---------+---------+----------+
    | 12  | /VSYNC    | Vertical sync.        | *Sync.  | No sync | Sync.    |
    +-----+-----------+-----------------------+---------+---------+----------+
    | 13  | BLU.GND   | Blue video ground     | GND     | GND     | GND      |
    +-----+-----------+-----------------------+---------+---------+----------+
    | 14  | HSYNC.GND | HSYNC ground          | GND     | GND     | GND      |
    +-----+-----------+-----------------------+---------+---------+----------+
    | 15  | /HSYNC    | Horizontal sync.      | Sync.   | No sync.| No Sync. |
    +-----+-----------+-----------------------+---------+---------+----------+

    Note:
    Bullets (*) indicate where the differences are in the two sleep functions.


    Going Into a True Sleep Mode (No Power)

    Here is one method you can use to have the display go into a true sleep mode (no power).

    Step 1
    Open the Energy Saver control panel

    Step 2
    Set the System sleep option to the minimum value (30 minutes).

    Step 3
    If you want the display to go into a low-power sleep mode (loss of video only) then select display sleep and set the time for under 30 minutes. If you want the display to go into a true sleep mode (loss of power), deselect display sleep and have the system sleep set at 30 minutes or greater. If you have an option for never, all three options for sleep including the display are set for never.

    Step 4
    Close the Energy Saver control panel


    The CPU sleep blanks all Video, Horizontal and Vertical Sync, and Composite Sync. With the display sleep function selected and set at under 30 minutes, you lose only video and composite sync. The display will not lose power until the CPU goes to sleep.

Document Information
Product Area: Mac OS System Software
Category: General OS
Sub Category: General Topics

Copyright © 2000 Apple Computer, Inc. All rights reserved.