Rev 1.0
1/27/14
49
49
Reference Guide
Recommendations when Using
the USR3500 on Trucks
7.2. Technical Constraints on Trucks
It is highly recommended to directly connect the power supply on the circuit breaker
rather than on the battery. The modem may be damaged when starting the truck if
the circuit breaker is switched OFF (in this case, the truck ground and the battery
ground will be connected through the modem as shown in the following figure).
Figure 28. Example of an Electrical Connection That May Damage the modem
The figure above gives an example of an electrical connection which may
dramatically damage the modem when its ground connection is directly connected to
the battery ground.
In this example, when the circuit breaker is switched OFF, the current flows through
the modem and powers the electrical circuit of the truck (for example, the
dashboard). Furthermore, when the Starter Engine command is used, it will destroy
the cables or the modem.
Since the internal tracks of the modem are not designed to support high currents (up
to 60A when starting the truck), they will be destroyed.
