User guide
Table Of Contents
- Presentation
- Warning
- Copyright
- 1 References
- 2 Packaging
- 3 General presentation
- 4 Characteristics and Services
- 5 Use of the modem
- 5.1 Starting with the modem
- 5.2 Specific recommendations for the use of the modem in vehicles
- 5.3 GSM led of the modem
- 5.4 Echo function of AT commands deactivated
- 5.5 Checking the quality of the GSM reception signal
- 5.6 Verification of PIN code
- 5.7 Verification of modem registration on GSM network
- 5.8 Verification of modem registration on GPRS network
- 5.9 Verification of internal voltages of the modem
- 5.10 Main AT commands (HAYES)
- 5.11 Turning OFF the modem
- 5.12 Updating procedure of the modem
- 6 Trouble Shooting
- 7 Functional description
- 8 Technical characteristics
- 8.1 Mechanical characteristics
- 8.2 Electrical characteristics
- 8.3 Environmental characteristics
- 8.4 Standards/Conformities
- 9 Security recommendations
- 10 Recommended accessories
- 11 Client support
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Descriptions and non-contractual illustrations in this document are given as an indication only.
ERCO & GENER reserves the right to make any modification.
Dct_427_01
5.2.2 Technical constraints in trucks
It is highly recommended NOT to connect the modem supply directly to the battery but to the circuit breaker.
Otherwise the modem can be damaged when the truck is starting up if the circuit breaker is closed (in this
case, the ground of the truck and the ground of the battery will be connected via the modem as described in
the scheme below).
Figure 16 : Example of forbidden electrical connection (risk of damage on the modem)
The scheme above shows an example of electrical connection that could damage the modem due to the fact
that the ground connection is directly connected to the battery ground.
In fact in this example, when the circuit breaker is open, the current escapes via the modem and the
electrical circuits of the truck (the dashboard for example). And when the motor’s starter is used, it will
destroy the cables or the modem.
Moreover, the internal circuits of the modem are not designed to resist to a current of about 60 A (when
starting the truck), or they would be destroyed.