POP full form

What is the full form of POP?

  • Post Office Protocol

What does POP mean?

POP stands for post office protocol. It is most commonly used as a protocol to retrieve e-mail from a mail server. Most of the e-mail application is used as a POP protocol, although some can use the newer IMAP access protocol. 

There are two versions of POP called as a POP2 and POP3. The first called POP2 became a standard in the mid-'80s and it requires SMTP to send a message. The second one and newer version POP3 can be used with or without SMTP.

Difference between dwdm and cwdm

CWDM and DWDM both are effective methods to solve the increasing bandwidth capacity of information transmission at present. The main development goals of CWDM and DWDM are both high capacity and also low cost. but the difference between CWDM and DWDM is as given below:

The main key difference between DWDM and DWDM is listed below:
  • DWDM stands for dense wavelength division multiplexing, CWDM stands for coarse wavelength division multiplexing, 
  • CWDM defined by wavelength, DWDM defined by frequencies.
  • CWDM has lower capacity, DWDM has higher capacity.
  • CWDM has lower cost, DWDM has a higher cost.
  • CWDM has short-range communication, DWDM has long-range communication.
  • CWDM has used a wide range of frequencies, DWDM uses a narrow range of frequencies.
  • In DWDM cooled laser may be used due to tighter control of wavelength, Whereas in CWDM uncooled laser is used due to the longer channel spacing 
  • In CWDM break spectrum is large in a large section, While in DWDM break spectrum in smaller sections
  • CWDM is more wavelength spacing, While DWDM has less wavelength spacing.
  • DWDM precision laser is needed to keep channels on the target, while in CWDM wavelength drift is possible.
  • CWDM has Mux and Demux systems are developed to be used in multiplexing multiple, CWDM channels into one or two fibers.
  • In CWDM no of active wavelength per fiber is fewer than 8 while DWDM more than 8.
  • DWDM is used for application for light signal amplification.
  • DWDM systems are capable to fit more than forty different data streams in the amount akin to that of fiber used for two data streams in a CWDM system.
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CWDM full form

What is the full form of CWDM?

  • Coarse Wavelength Division Multiplexing

What does CWDM mean?

CWDM is a wavelength multiplexing technology for the city and also it accesses the network. Transmission is realized using total of 18 channels wavelength between 1270 nm and 1610 nm. Due to the channel spacing of around 20 nm, cost-effective lasers can be used. The channel width itself is 13 nm. The remaining 7 nm designed to secure the space to the next channel.

Advantages and disadvantages of FDM

The most important application of FDM (frequency division multiplexing)  is broadcasting, telephone communications. In this article, you will find a lot of pros and cons of FDM to better understand this topic. 

Advantages of FDM:
  • It does not need synchronization between its transmitter  as well as receiver
  • FDM is simpler and easy demodulation
  • Less expensive
  • FDM system does not need synchronization but TDM needs synchronization. It is an advantage of  FDM over TDM
  • FDM provides more latency than TDM
  • Using FDM system  multimedia data can be transferred with very high efficiency and low noise and distortion 
  • FDM system has high reliability
  • It is used for analogue signals
  • In this system due to slow narrowband fading, only one channel gets affected
  • A large number of the signal can be transmitted simultaneously

Disadvantages of  FDM:
  • It is suffering the problem of cross talk
  • FDM is only used only when a few low-speed channels are desired
  • Intermodulation distortion takes place
  • The  circuitry for FDM is complex than TDM
  • FDM requires more hardware than TDM
  • FDM system extremely expensive
  • FDM provides less throughput
  • FDM has not dynamic coordination
  • The full bandwidth of the channel cannot be used on the FDM system
  • The communication must have very large bandwidth
  •  A large number of modulator and filter required 
  • FDM channel can get affected wideband fading 
  • FDM system needs a carrier wave or carrier signal but TDM does not need carrier signal
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2G technology features

2G technology uses digital signals and this digital signal uses for voice transmission. This signal provides services to deliver text and picture message at low speed (in around kbps range). Here this post gives information about 2G technology features to better understand this topic.

2G technology is a second-generation wireless telephone technology, It is based on the technology known as the global system for mobile communication or in short we can say GSM. 2G technologies enabled the various mobile phone network to provide services such as text message, picture message, and also  MMS called multimedia messages. All text message is digitally encrypted. This digital encryption allows for the transfer of data in such a way that only the intended receiver can receive and read it.

Basic key features of 2G technology:
  • Utilized digital signal processing rather than the analog signal used in 1G.
  • Digital signaling processing allowed the network to support data transfer as well as the voice traffic previously supported by analog signaling
  • 2G became very popular because the user was capable of connecting their mobile devices to the internet and business work.
  • It supports phone calls.
  • It provides better quality and capacity.
  • It supports MMS
  • 2G technology has steadily improved with increased bandwidth as well as packet routing, and the introduction of multimedia.
  • 2G provided speeds of 135 Kbps to customers at its peak.
  • It can uses send/ receive an email message.
  • 2G is a digital version of 1G technology.
  • 2G technology became very popular because users were capable of connecting their mobile device to the internet and business networks.
  • 2G technology is utilized in digital signaling processing rather than the analog signaling used in 1G.
  • 2G technology support voice as well as data.
  • TDMA, as well as CDMA technology, must be used for multiple access
  • 2G technology must be used digital signal processing so it allowed a network to support data transfer as well as the voice traffic previously supported by analog signaling.
  • 2G became very popular because the user was capable of connecting their mobile devices to the internet and business network.
  • It takes time 6 to 9 minute  to download a 3 minute MP3 songs

Difference between zigbee and wifi

Zigbee technology is designed to carry a small amount of data over a short distance while it consuming very little power, while in WiFi is a mesh networking standard, meaning each node in the network is connected to each other. This post gives information about the difference between ZigBee and wifi to better understand this topic.

The main key difference between Zigbee and WiFi is given below:

  • Zigbee has IEEE 802.15.4 and ZigBee Alliance, While Wifi has IEEE 802.11 series.
  • Zigbee as WPAN network, WiFi has WLAN network type.
  • Zigbee has 868/915 band and 2.4 GHz frequency, WiFi has 2.4 GHz and 5 GHz.
  • Zigbee has about 1 MHz channel bandwidth, while WiFi has 0.3 to 0.6 or 2 MHz channel bandwidth.
  • Zigbee has star and mesh type topology used, WiFi has BSS, ESS configuration used.
  • Zigbee has BPSK, OQpsk modulation type while WiFi has OFDM, CCK, QPSK,64QAM, 16QAM,256QAM modulation techniques used.
  • Data rate up to 250 Kbps low data rate, while WiFi up to 54 Mbps using 802.11a/g/OFDM technique, even more, is achievable using 802.11n, 11ac,11ad standard based products.
  • In Zigbee typical distance coverage around 10 to 30 meters, while WiFi 30 to 100 meters distance covered.
  • Zigbee managed by alliance and IEEE, WiFi Alliance and IEEE.
  • Number of RF channel in ZigBee 1(868MHz), 10(915MHz), 16(2.4GHz)  while WiFi 14(2.4GHz)
  • Zigbee chip cost $2 less per device than WiFi device at high volume.
  • Zigbee chip or module has a power consumption of 0.39 watts over WiFi chip of 0.87 watts.
  • Transmitted power of ZigBee is -25dbm to 0 dBm while WiFi 15 to 20 dBm.
  • Data protection using CRC is 16 bit while WiFI 32 bit CRC.
  • Zigbee is used for home automation, while WiFi is used for cellular connection within home.
  • Popular Zigbee chip is Freescale, Texas, Marvell, ATMEL, Microchip while WiFi chip Texax instruments, redpine, microchip, Broadcom, etc.
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Advantages and disadvantages of microcontroller

This post gives information about the advantages and disadvantages to better understand this topic.

Advantages of the microcontroller:
  • The low time required for performing the operation
  • It is easy to use, troubleshooting and system maintenance is simple
  • At the same time, many tasks can be performed so the human effect can be saved
  • The processor chip is very small and flexibility occurs
  • Due to their higher integration, cost and size of the system is reduced
  • The microcontroller is easy to interface additional RAM, ROM, and I/O port
  • Once microcontroller is programmed then they cannot be reprogrammed
  • Without any digital parts, it can act as microcomputer
  • It is easy to use, troubleshooting and system maintaining is simple
Disadvantages of the microcontroller:
  • It is generally used in micro equipment
  • It has a more complex structure as compared to microprocessor
  • The microcontroller cannot interface a higher power device directly
  • It only performed a limited number of executions simultaneously