What are the Network Bands Used in India for 2G, 3G and 4G ???

               Network frequency bands are often overlooked while purchasing any smartphone. Network bands are important related to coverage and data speed on your mobile. So, we will discuss about different network bands used in India on GSM, HSPA or UMTS and LTE.

What is a Network Band ?

             Network band is a specific range of frequencies in a spectrum. With each band defined Upper and down limit. By default Spectrum is government property and it is leased by carriers for fixed amount of time. Government agencies allocates spectrum in auctions to various network carriers.

             In India, Telecom Regularity Authority of India is responsible for spectrum allocations. Spectrum is allocated to network carriers Like Airtel, Vodafone, Jio, Idea, BSNL for interference free and unlimited usage. Before proceeding further, we must discuss some useful terms

Spectrum:

Spectrum is collection of various types of electromagnetic radiations of different wavelengths. In simplified words, Spectrum is airwaves on which signals of network carrier travels.

LTE

Full form of LTE is Long term evolution and often referred as 4G. LTE is an standard for high speed wireless communication for mobile phones and data terminals.

GSM

Full form of GSM is Global System for Mobile communications. GSM is a standard for defining 2nd Generation of digital telephony which offers internet services on mobiles but relatively very low speeds.

HSPA

Full form of HSPA is High Speed Packet Access. HSPA is combination of HSDPA (High speed downlink Packet Access) and HSUPA (High Speed Uplink Packet Access). It is an standard defined to improve performance of 3rd generation (3G) digital telephony with relatively much higher speeds than its predecessor 2G.

Downlink

Downlink means transfer of signals from base station to mobiles.

Uplink

Uplink means transfer of signals from mobiles to base station.

Network Bands Used in India

In India, GSM telephony works on two different frequency bands GSM900 and GSM1800 in MHz(mega hertz). Lower frequency network bands offers higher coverage while higher frequency network bands offers higher data speeds.

HSPA telephony in India works on two different network bands UMTS900 and UMTS 2100 in MHz. UMTS network bands are radio frequencies used by 3G. UMTS network bands in India are commonly deployed at 2100 MHz for better speeds.

LTE Technology in India make use of 3 network bands namely 
LTE850 (Band 5), 
LTE1800(Band 3),
LTE2300 (Band 40). 

Band 3 provided great network coverage while Band 40 0ffers greater data speeds.

Band 3

Among different network bands, Band 3 is already used by various network companies in India to provide 2G services. Band 3 runs on 1800 MHz spectrum and provides an superb ecosystem in world to deploy LTE services to users. In auction of 2015, almost every cellular company leased out Band 3 spectrum to provide their services. In India, Jio, Airtel, Vodafone, Idea, Reliance, Telenor, Videocon bags out 1800 MHz band to provide their 4G services. Only BSNL and Tata Docomo were not able to lease out this frequency band.

Band 5

Band 5 is another out of another network bands that your smartphone should support. Band 5 runs on 850MHz which results into best network coverage. Reliance Jio has already launched its LTE services on Band 5 and network is available in almost every part of the country. Apart from Jio, BSNL, MTS and Docomo also hold this spectrum in their polythenes. Earlier smartphones does not included support for this band because it provides poor 4G speeds but best network reception on 4G network. But after Jio and their VoLTE smartphones, now smartphones includes support for Band 5 as well.

Band 40

Another Popular Network Bands used includes Band 40 which run on radio frequency of 2300 MHz. It is specially used by 4G networks to provide their services with great data speeds. Currently, Airtel, Jio, Aircel and Tikona uses this spectrum for its service deployments. Band 40 is also supported on almost every 4G smartphones in India. Reliance Jio holds PAN India license for 2300 MHz spectrum and already launched it throughout the country.

Note : Reliance Jio uses all of three LTE network Bands namely Band 3, Band 5, Band 40. All three bands are required for VoLTE services and superb data speeds on Jio SIMS. Choosing Band 5 will provide better network reception while choosing Band 40 will provide greater data speeds on your mobile.

Better speed:  2300Mhz > 1800Mhz > 850Mhz

Better coverage:  850Mhz > 1800Mhz > 2300 Mhz

What is the difference between Null Modem cable and Straight Through Cable...???

             The null modem cable is frequently called a Crossover cable. It is used to allow two serial Data Terminal Equipment (DTE) devices to communicate with each other without using a modem or a Data Communications Equipment (DCE) device in between. For this to happen, the Transmit (TXD) pin of one device needs to be connected to the Receive (RXD) pin of the other device.  To enable handshaking between the two devices, the Request to Send (RTS) pin of one device must be connected to the Clear to Send (CTS) pin of the other device. Because these pins are "crossed" on the two cable terminals, the name crossover cable is used.


                            DB9 - Null Modem Cable (Female - Female Connectors)

Null Modem Cable with Handshaking

               A straight-through cable is used to connect a DTE device to a DCE device. The TXD-RXD and RTS-CTS pins are not cross-connected in this case, hence the term straight through cable.

Simple Straight Through Cable

DB9 - Straight Through Cable(Male - Female Connectors)

               The built-in serial port on a PC is a DTE device. Modems and printers are examples of DCE devices.  Note that an instrument with serial interface could be either a DTE or a DCE device.  It is best to check the user manual of the instrument to find out the device type.  For more information regarding DTE and DCE devices, please see the links below. 

To tell if your cable is null modem or straight though, you can search the part number at ni.com, the product description will tell if it is null modem. Alternatively you can use a hand held DMM to test continuity on the individual pins of your serial cable. If every pin is electrically connected to the corresponding pin on the other end, i.e.: pin 1 to pin1, pin 2 to pin 2, etc. then the cable is straight through.

What is the difference between DCE and DTE ???

           DTE is the source or destination of digital data, while DCE is the equipment used to transmit or receive the data. DTE stands for Data Terminal Equipment, while DCE stands for Data Communications Equipment.

          Examples of devices that are DTEs include computers, printers and routers. They are all devices that act as the source or destination for data, but they are not concerned with the communication of data between devices. The most common usage of the word is in relation to RS-232C standard serial communications.

          DCE, on the other hand, is concerned with the communications aspect of data. This means it communicates with a DTE. So a DCE takes data from a DTE, converts it into a signal that can be transmitted, and transmits it, usually to another DTE.

         One of the most common examples of a DCE device is a modem. It communicates data from the internet to a DTE, which could be a computer, a tablet or a smartphone. Other DCE examples include ISDN adaptors,network interface cards. Also, as well as being responsible for the communication, DCE devices are often responsible for the timing over a serial link too.

Some examples of DTE and DCE devices:

1.PC - PCI Cord - DTE

2.DCE and DTE Pinout:

3.Communication Network:

Sources : www.reference.com

What’s the Difference Between Sleep and Hibernate ?

Sleep Mode

Sleep mode is a power-saving state that is similar to pausing a DVD movie. All actions on the computer are stopped and any open documents and applications are put in memory. You can quickly resume normal, full-power operation within a few seconds. Sleep mode is basically the same thing as “Standby” mode.

The Sleep mode is useful if you want to stop working for a short period of time. The computer doesn’t use much power in Sleep mode.

Hibernate

The Hibernate mode saves your open documents and running applications to your hard disk and shuts down the computer, which means once your computer is in Hibernate mode, it uses zero power. Once the computer is powered back on, it will resume everything where you left off.

Use this mode if you won’t be using the laptop for an extended period of time, and you don’t want to close your documents.

Source : Howtogeek

Difference between USART, UART, RS232, USB, SPI, I2C, TTL ...

UART - Universal Asynchronous Receiver Transmitter:

• It is one of the most used serial protocols.
• Most controllers have a hardware UART on board.
• It uses a single data line for transmitting and one for receiving data.
• Most often 8-bit data is transferred, as follows: 1 start bit(low level), 8 data bits and 1 or 2 stop bit(high level).
• The low level start bit and high level stop bit mean that there's always a high to low transition to start the communication.That's what describes UART.
• No voltage level, so you can have it at 3.3 V or 5 V, whichever your microcontroller uses.
• Note that the microcontrollers which want to communicate via UART have to agree on the transmission speed, the bit-rate, as they only have the start bit's falling edge to synchronize.That's called asynchronous communication.
• For long distance communication (That doesn't have to be hundreds of meters) the 5 V UART is not very reliable, that's why it's converted to a higher voltage, typically +12 V for a "0" and -12 V for a "1".
• The data format remains the same. Then you have RS-232 (which you actually should call EIA-232, but nobody does.)
• The timing dependency is one of the big drawbacks of UART, and the solution is USART, for Universal Synchronous/Asynchronous Receiver Transmitter.

USART - Universal Synchronous/Asynchronous Receiver Transmitter:

• This can do UART, but also a synchronous protocol.
• In synchronous there's not only data, but also a clock transmitted.
• With each bit a clock pulse tells the receiver it should latch that bit.
• Synchronous protocols either need a higher bandwidth, like in the case of Manchester encoding, or an extra wire for the clock, like SPI and I2C.

SPI - Serial Peripheral Interface:

• It is another very simple serial protocol.
• A master sends a clock signal, and upon each clock pulse it shifts one bit out to the slave, and one bit in, coming from the slave.
• Signal names are therefore SCK for clock, MOSI for Master Out Slave In, and MISO for Master In Slave Out.
• By using SS (Slave Select) signals the master can control more than 1 slave on the bus.
• There are two ways to connect multiple slave devices to one master, one is mentioned above i.e. using slave select, and other is daisy chaining, it uses less hardware pins(select lines), but software gets complicated.

I2C - Inter-Integrated Circuit (pronounced "I squared C"):

•  It is also a synchronous protocol, and it's the first we see which has some "intelligence" in it; the other ones dumbly shifted bits in and out, and that was that. I2C uses only 2 wires, one for the clock (SCL) and one for the data (SDA). 
• That means that master and slave send data over the same wire, again controlled by the master who creates the clock signal.
• I2C doesn't use separate Slave Selects to select a particular device, but has addressing.
• The first byte sent by the master holds a 7 bit address (so that you can use 127 devices on the bus) and a read/write bit, indicating whether the next byte(s) will also come from the master of should come from the slave.
• After each byte receiver must send a "0" to acknowledge the reception of the byte, which the master latches with a 9th clock pulse. If the master wants to write a byte the same process repeats: the master puts bit after bit on the bus and each time gives a clock pulse to signal that the data is ready to be read.
• If the master wants to receive data it only generates the clock pulses. The slave has to take care that the next bit is ready when the clock pulse is given.
• This protocol is patented by NXP(formerly Phillips), to save licensing cost, Atmel using the word TWI(2-wire interface) which exactly same as I2C, so any AVR device will not have I2C but it will have TWI.
• Two or more signals on the same wire may cause conflicts, and you would have a problem if one device sends a "1" while the other sends a "0".Therefore the bus is wired-OR'd: two resistors pull the bus to a high level, and the devices only send low levels.If they want to send a high level they simply release the bus.

TTL - Transistor Transistor Logic:

• It is not a protocol. It's an older technology for digital logic, but the name is often used to refer to the 5 V supply voltage, often incorrectly referring to what should be called UART.

Source : Electrical Engineering Stack Exchange 

Basic Differences Between Category cat5e, cat6, cat6e and 6a Network Patch Cables ....

                         

Category 5 through 6e cables look nearly identical for everyday people and at first glance but there are some subtle differences. There are differences that are visible and others that are not.

            Common network cables, also referred to as patch cables, look all so similar to each other. It's very difficult at times to tell them apart and for novice users, it is nearly impossible.

The most important difference between the cables is the speed and distance in which they operate most effectively. Speed and distance have a direct relationship when it comes to network cables and it's these two characteristics that differentiate cabling requirements.

Differences Between Network Cables

They may all similar but there is more to the small little wires inside the plastic cover. The number of twists even make a difference in range and speed based on frequency.

Differences Between Categories of Cables : Design, Characteristics

	CAT3	CAT5	CAT5e	CAT6	CAT6e
Maximum Data Rate (1 Twisted Pair)	10 Mbps	100 Mbps	1000 Mbps	10 Gbps	10 Gbps
Maximum Frequency	16 Mhz	100 Mhz	350 Mhz	250 Mhz	750 Mhz
Typical Distance	100 m	100 m	100 m	100 m	100 m
Maximum Distance at Maximum Data Transfer Rate			50 m	55 m

UTP cat5 through cat6a

4 Separate Pairs. This is a similarity between the various cables. They all use 4 pairs of wires.

UTP and Data Rating.

UTP is an acronym for Unshielded Twisted Pair. UTP data speed are expressed in megabits per second, or Mbps. You may have seen MB/s, this expression is mega BYTES per second. Although seemingly a symantec difference, it is not. BYTES with a capitol "B" is used for writing and reading from a storage device such as a hard drive whereas mega bits wit ha lowercase "b" is used during speed or transmission of data over a medium. Category 5 UTP cable up to 100 meters is rated for wire data speeds of up to 100 Mbps. Category 5e is rated up to 1000 Mbps (1000Mbps is 1 gigabit). Category 6 cabling is backward compatible which means it can be used for 10 and 100 Mbps applications and for rated speeds up to 1000 Mbps. Cat 6 can also perform at 10GB for very short distances. Category 6a, which has a speed rating of up to 10 gigabit (or 10,000 Mbps), is beginning to become more common as the price of network cards falls. As such was the case when the shift was from 10 to 100 then 100 to 1 Gbps.

Practical Uses for 10GB Networking

I have deployed 10GB in servers intended for virtualization. Which in short means one physical server can contain many virtual Windows servers . The virtual servers all share the physical network connections on the real physical server so 10GB is very useful in such a scenario. 10 GB on a desktop is impractical and really not worth the expense. 1 GB network cards are more than enough for a single computer.

Construction, pairs or wire count is the same

Category 5, 5e, 6, 6e, and 6a UTP has four pairs of twisted wires (Category although it is not used for data and was a phone system standard created long ago before Ethernet was the "standard cabling type". The reason why each pair of wires is twisted around each other is to allow one wire to cancel out any interference in the second wire in the pair. Category 5e and CAT5 have the same basic construction including the wire type and gauge , but with higher standards in manufacturing and installation such as and the number of twists per foot of each pair. Category 6 UTP is a slightly thick wire gauge. #22 instead of the #24 gauge wire for each pair found n 5 and 5e. It contains a contains a physical separator, a plastic separator that runs the length of the cable. It looks like a plus symbol when turned and viewed from a cut side and is the separator between the four twisted pairs to reduce electromagnetic interference between the pairs and reduce data noise.

Speed vs Cost Considerations

Consider the real and not "wish list" data speed requirements of your network. A first re-action is to want CAT6a everywhere as it will provide speeds of up to 10 gigabits. However, it use widely throughout a network is not practical yet and will yield no performance in creases as desktops are still at 1 GB and also at a cost 30 percent more than a comparable CAT5e network infrastructure. Generally as I've seen in many offices and data centers, CAT5e cabling is sufficient to support many 1Gb and 100Mb networks. Especially if the network devices such as switches and routers only support data speeds of 1000 Mbps. It's nearly inconceivable as to why some people don't upgrade but I still see 10Mbps too! - it is horrible.

Connectors, Pin assignments

Cat 6a STP RJ45 Plug

Basic Differences Between Category 5 and Category 6

Connectors for cat5 and cat5e cables are very much interchangeable and actually absolutely identical, but those for cat6 have subtle yet very distict required differences that are not easily visible but can be seen if looked at closely. All connectors are however are of the type RJ45 that we commonly see connected into our desktops and will fit into RJ45-type interface ports and sockets like those on our computers, firewalls, switches, et.. Pin assignments are also unmistakely identical for all of the three cable types and for cabling and patch cords sold as cat6e. The IEEE standards committee would have found a hard sell if pin assignments had been changed because that would have meant special new switches and that would have caused every switch manufacturer to have to design new switch ports. Because of the thicker #22 conductor wiring size, connectors for cat6 cables have slightly larger holes where each of the individual wires enters the connector. More importantly, the conducting connector material (meaning the small copper connectors we see at the end of a cable buil into the plastic connector) and the details of the conductor in each connector arrangement are designed to enhance transmission to match the characteristics of the cable.

Make Your Own Patch Cables

Straight-through pin-out RJ45 Ethernet

Making your Own Cables, It's Easy, The Wire Crimper is Key

It's not as hard as it seems and you can save some money too by making your own cables. The cost of wire is bad enough but the cost of patch cables already with ends on them is so very expensive.

The pin-outs below work. I have used them to make cables. The added tool required is a wire crimper. They are not pricey either but they are an additional cost. Borrowing one for a project is better of course.

Crossover Cables - A Special Case Cable

Ethernet Network Crossover Patch Cable pin-out and Straight Through cable pin-out.

There are cables that were called "cross-over" cables. They were much more common only a few years to a decade ago. Many, if not all, modern network switches and Ethernet interfaces on routers used in homes and business for Internet access, wireless access points, etc. have built-in cross-over detection. Which means that each port can detect if it needs to change "mode" to cross-over mode.

The need for Ethernet cross-over network cables existed because switches years ago were designed with interfaces for computers, and printers, or other "end point" devices. Simply, devices that had a single interface themselves were not a switch for multiple connections. When one switch was connected to another (actually hub to hub a little further back in time), a cross-over cable was needed because both connecting devices (each switch or hub) had multiple interfaces and were devices for multiple connections.

Cross-over network cables have a slightly different pin-tout. Pins are "crossed" on the transmit and receive. It is not as complicated or hard as it seems and a cross over cable can be made just as a normal "straight through" cable can be made. Special care needs to be taken to cross the correct wires.