Doc. Title
ST3940 User Manual
Concerning:
Rev.
Date (dd-mm-yy)
Page of Pages
Features and how to configure ST3940
1.06
0
18-6-19
25 of 54
Once jamming on the GPRS/HSPA network starts being
detected, the device will also check the distance between the
current location of the vehicle and the First geographical Point
(‘Fp’) where the jamming started being detected.
If the distance is greater than JAM_CHK_DIST for a while,
triggered by JAM_DET mode.
If ‘0’, skip this procedure.
Default: 500 meters.
JAM_CHK_TM
‘0’ ~ ’43200’
Sec
It is complementary to the function of GPRS/HSPA jamming
detection in an area ‘without GPS connectivity’ (‘No GPS’).
After detecting jamming first in such a bad GPS connecting
area, the device begins to count the 2 time-length factors (
A
and B
) to make a sum (
A + B = C
) if the vehicle moves in the
area:
A: time length that needs to complete the jamming
detection
B: time length that the vehicle driver needs to
complete driving in the area.
If
C
(the sum) is longer than the length of the jamming
detection (‘JAM_CHK_TM’) the device judges that jamming
was done in the area. Please refer to the table for more details.
If the device has not moved in the area, ignore jamming
detection until the jamming detection function is released.
If ‘0’, skip this procedure.
Default: 300 seconds.
