horizon with the best location being near the center of the roof. For more covert installs, directly under
the front or rear-windshields are also acceptable.
Examples of Good (Green), OK(Yellow) and Poor(Red) combo antenna placements
Examples OK(Yellow) and Poor(Red) internal antenna placements
5.2.3 Access to the SIM (Subscriber Identity Module) Card
When used in a GSM or iDEN network, each TTU uses a Subscriber Identity Module (SIM) card, which
should be inserted before you install the TTU for the first time. The SIM card is attached to the main-
board inside the housing of the TTU unit.
At some future time, you might need or want to replace the SIM card with a different one, so try to
install the TTU in such a way that the cover can be removed to make the SIM card accessible.
5.2.4 Protection from Heat
It is best not to place the TTU unit in an unusually warm location such as directly near heater vents,
near hot engine components or in direct sunlight. The maximum temperature that can be tolerated by