Yes, the Indian Law permits License Free walkie talkie in the 27 MHz band but this frequency band interferes with other wireless products

No, VHF radio operate in the VHF 136-174 MHz range and IHF radio operates in the UHF 400-470 MHz and 350-390 MHz range. Since radios need to operate on the same frequency in order to talk to each other.

Cost and group contact capabilities. Two way radios are easy to use with a push-to-talk feature which enables the user to communicate instantly with anyone or an entire user group on the network.

Two way radio coverage is dependent on power, antenna height and terrain. On site portable radios will typically cover from 1-3 Km in radius (4-5 Watt UHF/VHF radios), while wide area radios can offer coverage up to a 10-15 Km radius with a repeator.

Depending on: work cycle, battery chemistry and charging cycle one should expect 1 to 2 yrs. Like a cellular phone, talk time also varies but you can expect up to 10 hrs per day.


Each booster improves one or a few networks. It can be GSm/DCS, 3G and 4G. GSM booster only voice, EDGE and GPRS, while 3G repeator is used to boost 3G mobile internet on many devices

Booster should got CE and ROHS approvals which guarantee that the equipment doesn’t contain any hazardous substances. All the Stark signal boosters got CE and ROHS approvals which guarantee that the signal boosters will not harm the humans.

Mobile signal booster’s working principle is quite easy. An outdoor antenna receives a signal from a mobile base station and transmits it to a booster. The device amplifies the signal and spreads it all over the area with an indoor antenna. Booster works in a duplex mode, which means that it not only gets the signal from the mobile tower but upon receiving sends it back.

Check that the distance between the outdoor and indoor antennas is at least  meters. If the distance is less, change their location.

As soon as you finish the installation and plug the booster into a power supply, you will see LEDs light up. It means the booster has been mounted correctly and it has started amplifying mobile signals all over the area. You can also check it with your mobile phone.


A user simply blow through the mouthpiece for 5 seconds blowing is similar to blowing out a candle and the user should blow evenly for the entire 5 seconds. The breathalyzer will indicate when to start and stop blowing, and if the samples was not adequate for an accurate reading.

The sensors measure the alcohol level of air in the deep lungs. This value is converted into the corresponding blood alcohol content (%BAC) estimate.

Replacing the mouthpiece after each test is optional if you are testing yourself for professional testing and screening, it is recommended to change the mouthpiece after each test because of safety performance reasons.

Clean them with soapy water and rinse, or wash in a dishwasher

Professional Breathalyzers provide the following benefits over Personal Breathalyzers:

  • They will not show a false positive for someone who is diabetic or on a low calorie diet. Semiconductor models will sometimes show a false positive result for these individuals.
  • They provide more accurate and more consistent results as compared with semi-conductor models. For example, you are more likely to show the same test result when you test someone repeatedly in a very short period of time. In addition, they are more accurate at higher BAC concentrations, compared to semiconductor models, which often lose accuracy at higher BAC values.
  • They can remain accurate for up to thousands of tests.
  • They provide more precise readings since %BAC readings are displayed to the thousandth decimal place (0.054%) versus to the hundredth decimal place (0.05%).


IP cameras send images digitally using the transmission and security features of the TCP/IP protocol.

  1. Connect IP cameras to PoE Switch.
  2. Configure DVR to your network.
  3. Configure cameras to your network.
  4. Add cameras to the XVR using its menu interface.

It could be argued that HD analog cameras are more secure, since they run on a closed circuit and don’t have an IP address. IP cameras, on the other hand, can be accessed directly via the Internet so they are more susceptible to security vulnerabilities.

Most IP cameras and professional NVR softwares support RTSP (Real Time Streaming Protocol). As long as they do, you can use them together without worrying about compatibility.

DVR stands for Digital Video Recorder, whereas NVR stands for Network Video Recorder.  Most NVRs are used with IP cameras whereas DVRs are used with analog cameras. It’s important to note that a DVR based system is a wired security system, whereas NVR systems can be a wired or wireless system


GPON stands for Gigabit Passive Optical Networks. … GPON can transport not only Ethernet, but also ATM and TDM (PSTN, ISDN, E1 and E3) traffic. GPON network consists of mainly two active transmission equipments, namely- Optical Line Termination (OLT) and Optical Network Unit (ONU) or Optical Network Termination (ONT).

EPON (Ethernet passive optical network) enables computer network connections over telecommunications infrastructure. EPON is quickly supplanting copper cable technology, DSL, and other traditional broadband access solutions.

Xpon is a next-generation technology company for the new era of marketing and customer experience. Our mission is to be the technology partner of choice for companies that are digitally transforming their marketing and customer experience capabilities.

Optical splitter has played an important role in passive optical networks (like EPON, GPON, BPON, FTTX, FTTH, etc.) by allowing a single PON interface to be shared among many subscribers.


VoIP gateway is a gateway device that uses internet protocols to transmit and receive voice communications (VoIP). The general term is ambiguous and can mean many different things. There are many such devices. They are quickly becoming the most common type of voice phone service in many areas

Any mobile device that is internet capable has a section in the settings that shows the strength of the Wi-Fi networks in range. For example, on an iPhone, open the Settings app, then go to Wi-Fi to see the Wi-Fi strength of the network you’re on and the signal strength of any network that’s in range

Different building materials block wireless signals to very different degrees. Wi-Fi signals are most weakened by having to go through thick walls, especially reinforced concrete

If you use a 2.4 GHz router and live in a densely populated area, like an apartment complex or a long row of townhomes, your neighbors‘ Wi-Fi networks could interfere with yours. If multiple wireless networks are competing for the same channel, this can cause problems.


No, because the electromagnetic signal sent by jammer are totally used in the band that regulated by government and just have interception effect to cell phone communication.

You should nit worry about it. The intensity of electromagnetic signal sent by jammer is in compliance with the national standard of environment electromagnetic wave health, the signal sent by jammer is relatively small and no damage will appeared on human body according to the testing files.

Yes, outdoor signals is bigger than the indoor signal. Thereby, the shielding effect is worse outdoor. Whether using indoor or outdoor, the effective distance of interception is related to the surrounding environment as the distance between base stations, positions of installation, etc.

The working distance is the most concerned point for the buyers. Usually, the distance is 10 m to 10 Km.


A hand held metal detector is an musical instrument that detects the presence of metal nearby. Metal detectors are useful for locating metal inclusions hidden within objects, or metal objects buried underground. They often contains a handheld unit with a sensor probe which may be swept over the bottom or other objects. If the sensor comes near a bit of metal this is often indicated by a changing tone in earphones, or a needle moving on an indicator. Usually the device gives some indication of distance; the closer the metal is, the upper the tone within the earphone or the upper the needle goes

The usage of handheld detector is various and enormous . In some public occasions the hand-held detector are often used for peace check like airports, jails, courts, testing centers, banks, hotels, bull sessions, athletic contests, vocal concerts then on. In some factories handheld metal detectors are wont to prevent the thievery who stole some products which contain metals. because the technology develops some student use tiny wireless headsets to cheat while testing, so as to against this behavior the education system requires the guards held a handheld detector outside of the examination room.

A detector is an instrument which detects the presence of metal. Metal detectors are useful for locating metal hidden within objects, or metal objects buried underground. A Door Frame detector (DFMD) because the name suggests may be a detector fitted during a door to detect metal which will be hidden on the body of the person passing through this door. this is often also referred to as a “walk through” detector . These are used for security screening at access points in prisons, courthouses, and at airports to detect concealed metal weapons on a person’s body.

Door Frame metal detectors (DFMDs) are of two types:

  • Single zone DFMD
  • Multi-zone DFMD provide multi zone detection


Door frame metal detectors are with higher sensitivity they will be utilized in the Jewellery manufacturing units to guard against pilferage. Use of such DFMD’s increases safety in prisons and jails by efficiently detecting small metal objects which will be used as weapons, even once they are hidden in body cavities. they’re also deployed in manufacturing and distribution facilities to guard small, valuable assets.

An under-vehicle inspection system is used to detect threats—such as bombs—that are hidden underneath vehicles. Cameras capture images of the undercarriage of the vehicle for manual or automated visual inspection by security personnel or systems.

Explosive detection is a non-destructive inspection process to determine whether a container contains explosive material. Explosive detection is commonly used at airports and for border control.