RadioShield

“RadioShield” from A.C.S.I. srl is a security product designed to shield a defined area around the device. The system is based upon an electronic circuit that generate an interfering radio signal over the frequency band used by the base stations of the cellular network. Due to this interfering signal all digital data from the base station present in the covered area of “RadioShield” will be distorted and unusable by the cellular terminal. The result is that all the cellular phones present in the covered area will not able to remain locked to the network, indicating “No field” on the screen and, at the side of the caller, will be received a message: “ user unreachable”.

As we said above “RadioShield” uses signals perceived only by the cellular phones and not by the base station of the cellular network ; this is very important because thanks to this system there is no way to interfere with other user of the cellular network except that are in the coverage area of the device. “RadioShield” operates only as a shield for the user and not as a wide area jammer that hits unwanted users of the network. Only for few cases, where the security is the primary target without compromise, is available the hi-power model, designed for wide area coverage and a rugged construction for hard environmental conditions.

The coverage area is strongly affected by tree main factors:

• The antenna features;
• The distance from the nearest base station;
• The output power of the “RadioShield”;

the used type of the radiating antenna determine how kind of shape will have the covered area: an omnidirectional antenna will produce a circular shielded area around the “RadioShield” while a directional antenna can selects different coverage areas; for example we can use a 180 degrees directional antenna to protect a room with “RadioShield” installed on the wall, without interfere with the room behind the same wall. Our hand held device has integrated a general purpose omnidirectional antenna but different solutions are available upon requests.

Due to the base stations transmit with several watts, near the tower will be more difficult to protect ourself against the signals because they are very strong but due to the square ratio of power decreasing respect to the distance from the source, a few hundreds of meters from base station will be sufficient to obtain good performances form “RadioShield”.

the power out of the device is another factor that determines the performance of the shielding; because this parameter can cause unwanted interference to the network users outside the targeted area, the “RadioShield” user must keep the power of the device as low as possible to cover the desired area. A power control divided into three step is provided on the control panel of “RadioShield”, in this manner the user can select output power as low as 1% of the maximum power of the device. As above, the high power model has a power output of about ten time the hand held model and, due to the ability to cover wide areas and a great number of cellular users, must be used by very qualified personnel only.

“RadioShield” is designed to cover two cellular phones bands: first from 800 MHz to 1 GHz and the second from 1,8 GHz to 2,0 GHz with output power from 0,8W maximum up to 10W depends on the selected model. The shielding signal, based on a low interfering white gaussian noise, ensures the compatibility with a great number of cellular network standards. Below the principal technical features for the available model of “RadioShield”.

Due to the particular uses of this device, that involve sensitive fields like security and communications, we need to prevent an unauthorized use of the “RadioShield”.

The best way to prevent these kind of unauthorized uses is to implement in the device’s control unit a “coded turned on” be founded on the two pushbutton present on the control panel.

Thanks to this button is possible to insert, by the authorized user, a code (unique for the device) that is recognized by the internal control unit that activate the device.

The silk screen printing of the frontal panel is very simple and will not be modified for code insertion purposes: only authorized personnel will know the procedure and the code. Others people that attempt to turn on the “RadioShield” by a simply (and common for commercial devices) pressure of the “ON” button will have no response from the device and probably think that the device is discharged or damaged. The turn on sequence is initiated pressing the button “POWER” and, hold on this button, inserting the numeric code (sequence of pressure) by use the “ON” button; the code is composed by three number. Every time a press sequence is completed we must release the “POWER” button to confirm, and first of the three power led turn on to indicate the ok to next number. The procedure described above will be repeated three time and at the end the green led on the right will turned on to indicate the device is operative. The sequence is quite long but extremely secure against unwanted use of “RadioShield”. To turn off the device, instead, a single pressure of the “ON” button is sufficient.

Thanks to the powerful control unit of the “RadioShield”, an RS232 connection is ready to use, in conjunction with a PC, to obtain advanced control over the device. Below some example:

• Remote device activation via Internet, LAN or simple PC
• Remote control of the emitted power bypassing the button on the frontal panel
• Time limited license activation via Internet
• Remote turn on and off by supervisor of the device
• Device diagnostic
• Device identifying

As you can see “RadioShield” is ready to be strictly controlled by authorized personnel, avoiding every unwanted use. “Coded turned on” and RS232 connection, are important features that permit a controlled and monitored only use of the device ensuring overall security and respect of the people right to communicate.

Frequency bands 0.8-1.0 GHz 1.8-2.0 GHz 2.1-2.2 GHz Total output power 450 mW Compatibility All world cellular standards Power supply 10–14 Vcc (battery powered version) Power consumption 700 mA 1 A (battery powered version) Autonomy 1 Hour (battery powered version) Charging time 4 Hour (battery powered version) Dimensions and weight 32 x 20 x 3 cm, 500 g

“Radioshield” achieved CE marking and ISPESL certification.

In base of current laws, the device cannot be sold inside European Community.