Hand Held Products 7900 - Manual (Page 162)

11 - 4 Rev F
10/16/07
Dolphin® 7900 User’s Guide
Suspend/Resume with GPS
When the terminal goes into suspend mode, power is removed from the GPS module. There are two ways to control the Suspend/
Resume activity of the terminal: via the keyboard or via activity timeout.
Suspend Via Keyboard Combination
Press Blue + Backlight keys.
Suspend Via Activity timeout
Dolphin terminals suspend when the device is inactive for a programmed period of time. The period of time is set in the Power
System Setting; see
Power on page 6-11. A GPS application can prevent this suspend by calls to SystemIdleTimerReset().
To determine the frequency to use to call SystemIdleTimerReset(), retrieve the following registry key:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Power
This function must be used appropriately! Keep in mind that a program that never suspends (or sleeps) by continually
calling SystemIdleTimerReset() quickly drains the battery.
Note: For complete instructions about Suspend/Resume in general, see Resetting the Terminal on page 2-11.
Time to First Fix (TTFF)
The duration of time spent in suspend mode affects the time it takes to acquire a positional fix when the terminal resumes normal
operations. This is known as “Time To First Fix” (TTFF).
Note: When the terminal boots up for the first time from the factory, TTFF can take up to 15 minutes.
Typical TTFF From No Satellite Data
The terminal stops acquiring GPS data when
1. The terminal goes into suspend mode, which can happen manually or due to device inactivity.
GPS data acquisition begins again when the terminal resumes normal operation. You have to wake the terminal manually
by pressing the Scan key. For more information, see
Resetting the Terminal on page 2-11.
2. The terminal moves to a location where it cannot receive satellite signals; inside a building that blocks satellite reception, for
example.
Typical TTFF
Type of Start Start Description Typical TTFF
Cold Start No satellite data has been received for 16 hours 80 seconds
Warm Start No satellite data has been received for 30 minutes 35 seconds
Hot Start No satellite data has been received for 15 minutes 10 seconds
!