Instructions

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4.1.2 GSM Signal strength
The modem has to be placed in a way that ensures sufficient GSM signal strength. To improve signal strength,
the antenna can be moved to another position. Signal strength may depend on how close the modem is to a
radio base station. You must ensure that the location, at which you intend to use the modem, is within the
network coverage area. Degradation in signal strength can be the result of a disturbance from another source,
for example an electronic device in the immediate vicinity. More information about possible communication
disturbances can be found in section 5.3.5.
When an application is completed, you can verify signal strength by issuing the AT command AT+CSQ. See
“AT+CSQ Signal Strength”.
Tip! Before installing the modem, use an ordinary mobile telephone to check a possible location for it. In
determining the location for the modem and antenna, you should consider signal strength as well as cable
length
4.1.3 Connections of components to HT910 Terminal
The integrator is responsible for the final integrated system. Incorrectly designed or installed, external
components may cause radiation limits to be exceeded. For instance, improperly made connections or
improperly installed antennas can disturb the network and lead to malfunctions in the modem or equipment.
4.1.4 Network and subscription
Before your application is used, you must ensure that your chosen network provides the necessary
telecommunication services. Contact your service provider to obtain the necessary information.
 If you intend to use SMS in the application, ensure this is included in your (voice) subscription.
 Consider the choice of the supplementary services
4.2 How to install the modem
4.2.1 Power supply
 Use a high-quality power supply cable with low resistance. This ensures that the voltages at the connector
pins are within the allowed range, even during the maximum peak current.
 When the unit is powered from a battery or a high current supply, connect a fast 1.25A fuse in line with
the positive supply. This protects the power cabling and modem.
4.2.2 Securing the modem
Before securing the modem take into account the amount of additional space required for the mating
connectors and cables that will be used in the application.
 Where access is restricted, it may be easier to connect all the cables to the modem prior to securing it in
the application.
 Securely attach the HT910 Terminal modem to the host application using two 3mm diameter pan-head
screws