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A network interface device (NID), also called network interface unit (NIU), is an interface between the network provider's local loop and the customer. These are present as grey boxes outside customer's premises, where the data wires of the phone company or the network provider ends and the customer's wiring begins. Diagrammatic Representation Features NID demarcates between provider's connection and customer's connection. Maintenance of wiring of the local loop up to the NID is the responsibility of the phone provider, while maintenance of wiring from the NID to the customer premises is the responsibility of the customer. NID protects ... Read More
Second generation (2G) mobile phones switched from analog system of 1G to digital system. It was commercially launched in 1991 as GSM standard in Finland. As with 1G phones, 2G phones didn’t have any worldwide standardizations. 2G systems were also known as personal communications services (PCM). Advantages of 2G over 1G It allows voice signals to be digitized and compressed. So, they are more efficient on frequency spectrum than 1G. They introduced data services for mobile in form of SMS text messaging. Data and voice signals are digitally encrypted. So, security against eavesdropping and fraud increased manifold. Digital signals ... Read More
Definitions Cable − Cable network is a system of providing varied services like television programming, FM programming, Internet and telephone services over existing cable TV network. ADSL − Asymmetric Digital Subscriber Line (ADSL) is a type of broadband communications technology to transmit digital data at a high bandwidth on existing phone lines to homes and businesses. Fiber − Fiber or Fiber to the home (FTTH) is a technology to deploy optical fibers in the local loop of the telephone networks to the users home for providing high-speed data connectivity. Comparisons Wires Cable − They use the copper coaxial ... Read More
Digital Advanced Mobile Phone System (D-AMPS)is a digital version of Advanced Mobile Phone Systems (AMPS), the original analog standard for cellular phones. D-AMPS uses a combination of time division multiple access (TDMA) and frequency division multiple access (FDMA). It adds TDMA to get three channels per AMPS channel, thus tripling the number of calls on a channel. Features They are standardised by IS-54 and IS-136. As in AMPS, D-AMPS also uses frequencies from 800 to 900MHz for transmission. Half of the spectrum is used for sending signals and the other half is used for receiving signals. The frequency ... Read More
In U.S. telecommunications,Local access and transport area (LATA) refers to a geographical area in the U.S. which is allocated to telephone companies. The telephone companies, legally termed as local exchange carriers (LECs) provide telecommunication services, within the allotted areas. A LATA may be within the same U.S. state or may span across more than one state, as laid down in Telecommunications Act of 1996. Two types of connections are possible. IntraLATA − It is a connection between two LECs within the LATA. InterLATA − It is a connection providing long-distance service between LECs in different LATAs.
Global System for Mobile communication (GSM) is the most widely used digital mobile telephony system. GSM technology was first launched in Finland in 1991. It was developed by European Telecommunications Standards Institute (ETSI) to describe the protocols for 2G mobile communications.Presently, GSM comprises of approximately 90% of mobile connections worldwide. Features Original 2G standard was a digital, circuit-switched, full duplex network. GSM is part of the evolution of wireless mobile telecommunications including High-Speed Circuit-Switched Data (HSCSD), General Packet Radio Services (GPRS), Enhanced Data GSM Environment (EDGE), and Universal Mobile Telecommunications Service (UMTS). GSM operates at either 900 MHz ... Read More
The network physical layer is the lowest network layer in the Open System Interconnections (OSI) model. The primary concern of this layer is transmission of individual bits from one node to another over a physical medium. In TCP/IP model, the physical layer and the data link layer are combined as the host - to - network layer. Physical Layer in the OSI Model The Open System Interconnections (OSI) model is a layered networking framework that conceptualizes how communications should be done between heterogeneous systems. The physical layer is its lowest layer. The following diagram depicts the position of the physical ... Read More
To get table names using SELECT statement, use “information_schema.tables”. Let us see an example, wherein we have a database that contains 3 tables. The syntax to get all table names with the help of SELECT statement. SELECT Table_name as TablesName from information_schema.tables where table_schema = 'yourDatabaseName'; Using database “test”, and applying the above syntax to get the table names using SELECT mysql> use test; Database changed mysql> SELECT Table_name as TablesName from information_schema.tables where table_schema = 'test'; Output with the name of the three tables. +--------------------+ | TablesName ... Read More
The network data link layer is the layer above the physical layer in the Open System Interconnections (OSI) model. The primary concern of this layer is to convert the raw transmission facility provided by the physical layer to a reliable and error-free link.In TCP/IP model, the physical layer and the data link layer are combined as the host - to - network layer. Data Link Layer in the OSI Model The Open System Interconnections (OSI) model is a layered networking framework that conceptualizes how communications should be done between heterogeneous systems.Its three lower OSI layers are called the network support ... Read More
When you compile Java programs using javac compiler it generates bytecode. We need to execute this bytecode using JVM (Java Virtual machine) Then, JVM translates the Java bytecode to machine understandable code. You can download JVM's (comes along with JDK or JRE) suitable to your operating system and, once you write a Java program you can run it on any system using JVM.