There is such an interesting data transfer protocol - APRS. A lot has already been told about him on the Internet. There will be no in-depth theoretical material here. This article will describe how to create your own "pocket" AFSK modulator. In the following articles there will be instructions for going on the air and for creating a simple demodulator. Which will allow you to accept APRS packages and display information on the display right on the street. Everything will be implemented for Flipper Zero. If you don't have this gadget yet, then don't worry and try everything on the great and terrible Arduino. It is very interesting to transmit information at a distance "with your own hands".
Development of communication systems *
A hub about all that concerns the development of communication systems
Does GPS transmit different data into LNAV and CNAV messages?
Different navigation message protocols are used for different navigation signal type. This is true even for a single system like NAVSTAR GPS. For example, L1C/A signals have a LNAV protocol, while L2C and L5 signals utilize a CNAV protocol. The newest L1C signal will use CNAV-2.
The protocol defines a data distribution into frames, subframes, the subframes structure, transmission intervals, data resolution and so on.
A navigation receiver use the navigation message data flow for several purposes:
1. The data flow allows to resolve a code ambiguity and set the signal time.
2. Ephemeris and clock values are used for the satellite position calculation, pseudorange corrections and coordinates computation.
3. The received data flow and navigation message data can be used for navigation symbols prediction. As result, we can use the wipe-off technique, expand discriminators and significantly increase tracking sensitivity:
The benefits of offering VoIP to your customers under your own brand
The potential of VoIP to your customers is simply phenomenal. Businesses are experiencing the advantages of VoIP’s cost-efficiency and reliability and now you can pass these benefits onto your own customers very easily. Cloud telecommunication is sophisticated and easily integrated. Confidence in this technology is growing fast. There has never been a better time to start talking to your customers about adopting this solution. It will deliver huge business benefits for them and has the potential to increase business income and profitability.
REST hooks for WebRTC Click to Call. Implementation experience
The "Click to Call" button on the website is an "innovation" that has been around for about 10 years. The technologies under the hood have changed, but the principle remains the same: someone clicks on the button on the site page, then JavaScript launches and requests access to the microphone and establishes a connection to the server — WebRTC SIP gateway. Further, the first client-server leg is a browser gateway, the second leg can be arbitrarily long and through the SIP proxy chain can eventually connect to a mobile or landline phone. Thus, the browser turns, in a sense, into a softphone and becomes a full participant in VoIP telephony.
Working with light: Starting your career at ITMO University
Simple and free video conferencing
Quantum communications at ITMO University: building 100% secure data transfer systems
Even more secret Telegrams
We used to think of Telegram as a reliable and secure transmission medium for messages of any sort. But under the hood it has a rather common combination of a- and symmetric encryptions. Where’s fun in that? And why would anyone trust their private messages to a third-party anyway?
TL;DR — inventing a private covert channel through users blacklisting each other.
Info desk: global Internet initiatives
Fiber-optic cables are a great way to bring high-speed Internet right to your home or office. But even in large cities not everyone can enjoy the benefits of it, since apartments far away from everyone, or low-population districts far from downtown, are very reluctantly served by ISPs.
And then there’s small towns and villages, far away from the main Internet “highways”. In poorer countries, Internet is often slow and expensive even in large population centers, while villages are often left without a connection for years. To connect them to the World Wide Web takes the resources of not just normal ISPs, but telecom giants. Solar-powered drones with networking equipment, weather balloons, satellites and other similar projects are not just science fiction, but a reality today (or in the near future). But who’s closer to launch and who’s lagging behind? Let’s find out.
Russian Internet Segment Architecture
The fault-resistance of an internet connection in any given region or country is tied to the number of alternate routes between ASes. Though, as we stated before in our Internet Segments Reliability reports, some paths are obviously more critical compared to the others (for example, the paths to the Tier-1 transit ISPs or autonomous systems hosting authoritative DNS servers), which means that having as many reachable routes as possible is the only viable way to ensure adequate system scalability, stability and robustness.
This time, we are going to have a closer look at the Russian Federation internet segment. There are reasons to keep an eye on that segment: according to the numbers provided by the RIPE database, there are 6183 autonomous systems in Russia, out of 88664 registered worldwide, which stands for 6.87% of total.
This percentage puts Russia on a second place in the world, right after the USA (30.08% of registered ASes) and before Brazil, owning 6.34% of all autonomous systems. Effects of changes in the Russian connectivity could be observed across many other countries dependant on or adjacent to that connectivity, and ultimately by almost any ISP in the world.
Authors' contribution
VASExperts 1399.0DmitrySpb79 1257.0MaFrance351 1249.0dmitriyrudnev 1040.0alizar 918.6zatim 688.0vsatman 680.0ptsecurity 611.0AlekDikarev 594.0EkaterinaLebedeva 473.0