Error detection and correction

1. network must be able to transfer data from one device to another device with a full
2. a system which can not guarantee the data received with data that is sent is useless
3. many factors that can cause data changed or deleted
4. system that can be in the trust (reliable system) must have menakisme to detect and correct data errors.


Type - type of error in data transmission
- Single bit
- Burst



Single bit error
Error only occurs in one bit.
Example:
In sending the letter A character
Letter A has a hex code 41 in binary code mean 0100 0001


Burst error
errors occur in more than one bit



Error detection

Error detection using the concept of redundancy is adding extra bits to detect an error when we get are geared toward.



Kinds of error detection method



VRC : vertical redundancy check (parity check)

LRC : longitudinal redundancy check

CRC : cyclical redundancy check

Standart WiFi (Wireless Fidelity)

IEEE 802.11a

• Maximum Data Rate is 54 Mbps
• Modulation : Orthogonal Frequency Division Multiplex (OFDM)
• Nominal ERP : + 16 dBm with 6dBi Antenna
• Range : 30 m (indoor) and 300 m (Outdoor)
• Maximum number user : up to 256 per Access Point
• Roaming berwen Acces Point

IEEE 802.11b

• 11 Mbps Maximum data rate per kanal
• Modulation DSSS ( Direct Sequence Spread Spectrum)
• Nominal ERP : + 10 - +23 dBm
• Range : 90 m (indoor) – 450m (Outdoor)
• Maximum number user : up to 256 per Access Point
• Roaming between Access Point

IEEE 802.11g

• 54 Mbps Maximum data rate per kanal
• Frequency : 2,40 – 2,4835 GHz
• Modulation : Orthogonal Frequency Division Multiplex (OFDM)
• Nominal ERP : + 10 - +20 dBm
• Range 100 m (indoor) – 400m (Outdoor)
• Maximum number user : up to 256 per Access Point

Roaming between Access Point

Signal

To convey information from the source to the information conveyed to the recipient
Definition of information: the characteristics of the source

Understanding analog and digital signals
- Analog signals: the signal at a specific time frame has a number of amplitude that is not limited
- Digital Signal: signal at a certain time span has a limited number of amplitude

Benefits of digital and analog signals
Digital signal
- Easy on the analysis
- Can be stored in electronic media
Analog signals
- Some can not be saved
- Susceptible to noise
- Little lost power

Microcontroller

microcontroller is an IC in which consists of several series that have their function - respectively, in general microcontroller or MCU has a function to control something, to be able to control something, in an embedded microcontroller can program in assembly language, Visual Basic or language c.
there are so many types of microcontroller used, but that I will discuss is the microcontroller ATMega8535.

to initiate the introduction of the microcontroller, I'll explain each of the pins on the microcontroller

Pin Descriptions

VCC Digital supply voltage.
GND Ground.
Port A (PA7..PA0) Port A serves as the analog inputs to the A/D Converter.
Port A also serves as an 8-bit bi-directional I/O port, if the A/D Converter is not used.
Port pins can provide internal pull-up resistors (selected for each bit). The Port A output
buffers have symmetrical drive characteristics with both high sink and source capability.
When pins PA0 to PA7 are used as inputs and are externally pulled low, they will source
current if the internal pull-up resistors are activated. The Port A pins are tri-stated when
a reset condition becomes active, even if the clock is not running.
Port B (PB7..PB0) Port B is an 8-bit bi-directional I/O port with internal pull-up resistors (selected for each
bit). The Port B output buffers have symmetrical drive characteristics with both high sink
and source capability. As inputs, Port B pins that are externally pulled low will source
current if the pull-up resistors are activated. The Port B pins are tri-stated when a reset
condition becomes active, even if the clock is not running.
Port B also serves the functions of various special features of the ATmega8535 as listed
on page 60.
Port C (PC7..PC0) Port C is an 8-bit bi-directional I/O port with internal pull-up resistors (selected for each
bit). The Port C output buffers have symmetrical drive characteristics with both high sink
and source capability. As inputs, Port C pins that are externally pulled low will source
current if the pull-up resistors are activated. The Port C pins are tri-stated when a reset
condition becomes active, even if the clock is not running.
Port D (PD7..PD0) Port D is an 8-bit bi-directional I/O port with internal pull-up resistors (selected for each
bit). The Port D output buffers have symmetrical drive characteristics with both high sink
and source capability. As inputs, Port D pins that are externally pulled low will source
current if the pull-up resistors are activated. The Port D pins are tri-stated when a reset
condition becomes active, even if the clock is not running.
Port D also serves the functions of various special features of the ATmega8535 as listed
on page 64.
RESET Reset input. A low level on this pin for longer than the minimum pulse length will generate
a reset, even if the clock is not running. The minimum pulse length is given in Table
15 on page 37. Shorter pulses are not guaranteed to generate a reset.
XTAL1 Input to the inverting Oscillator amplifier and input to the internal clock operating circuit.
XTAL2 Output from the inverting Oscillator amplifier.
AVCC AVCC is the supply voltage pin for Port A and the A/D Converter. It should be externally
connected to VCC, even if the ADC is not used. If the ADC is used, it should be connected
to VCC through a low-pass filter.
AREF AREF is the analog reference pin for the A/D Converter.

ORGANIZATION STANDART

1. ISO (International Standards Organization)

International Standard Organization (ISO) telah menetapkan standar layanan keamanan bagi suatu sistem terbuka ( open sistem ) yang memungkinkan interkoneksi antar sistem yang mengikuti model referensi dasar yang ditetapkan ISO. International Standard Organization (ISO) has set the standard of security services for an open system (open system) that allows the interconnection between systems that follow the basic reference model of the ISO defined.

Standar yang diterima secara umum dalam hal keamanan bagi sistem terbuka adalah ISO 7498-2-1988 Security Architecture, Part 2 - of ISO 7498, Open Sistem Interconnection-Basic Reference Model. Standards generally accepted in terms of security for open systems is ISO 7498-2-1988 Security Architecture, Part 2 - of ISO 7498, Open Systems Interconnection-Basic Reference Model.

ISO 7498 memberikan model referensi bagi komunikasi antar sistem terbuka (dikenal dengan Model Referensi OSI) dan ISO 7498-2 mencakup keamanan komunikasi untuk protokol OSI. ISO 7498 provides a reference model for communication between open systems (known as the OSI Reference Model) and ISO 7498-2 includes communications security for the OSI protocol.

ISO 7498-2 mendefinisikan lima layanan dasar untuk komunikasi sistem terbuka, yaitu: autentifikasi, kontrol akses, kerahasiaan data, dan non repudiasi. ISO 7498-2 defines five basic services for the open system of communication, namely: authentication, access control, data confidentiality, and non repudiasi.

ISO 7498-2 mendefinisikan lapis protokol yang bersesuaian untuk setiap layanan keamanan dan mekanisme yang dapat digunakan untuk implementasinya. ISO 7498-2 defines a protocol layer corresponding to each of the security services and mechanisms that can be used for implementation.

2. ITU - T (The International Telecomunications Union - Telecom Standards Sector)

International Telecommunication Union Radiocommunication Sector (ITU-R) Sebuah organisasi global yang ada dan didirikan untuk mengatur penggunaan frekuensi radio (RF) diseluruh penjuru dunia. International Telecommunication Union Radiocommunication Sector (ITU-R) A global organization that exists and was established to regulate the use of radio frequency (RF) in all over the world.

The United Nations (PBB), menugaskan kepada International Telecommunication Union Radiocommunication Sector (ITU-R) ini, untuk mengatur dalam hal skala penggunaan frekuensi, secara global. The United Nations (UN), assigned to the International Telecommunication Union Radiocommunication Sector (ITU-R) is, to manage in terms of frequency of usage scale, globally.
Nah, karena dunia ini luas, maka kemudian ITU-R membaginya menjadi beberapa wilayah. Well, because the world is wide, the ITU-R and then dividing it into several regions. Hingga masing-masing wilayah, diatur oleh organisasi yang berbeda. Until the respective regions, governed by different organizations.

Dalam ITU ada tiga organisasi utama : In the ITU there are three main organizations:

o Dewan Registrasi Frekuensi Internasional (IFRB, International Frequency Registration Board), bertindak untuk mendaftar menstandardisasi alokasi frekuensi radio The International Frequency Registration Board (IFRB, the International Frequency Registration Board), acting to register standardize radio frequency allocation
o Komite konsulatif untuk radio internasional (CCIR, Consulative Commite) mengatur norma untuk komunikasi radio Konsulatif Committee for International Radio (CCIR, Consulative Commite) set the standard for radio communications
o Komite konsulatif untuk telekomunikasi dan telegraph internasional (CCITT, Consultative committe on international telegraphy and telecommunicatons) berhubungan dengan standardisasi jaringan telekomunikasi internasional. Konsulatif Committee for telecommunications and international telegraph (CCITT, Consultative Committee on International telegraphy and telecommunicatons) associated with the standardization of international telecommunications network.

Beberapa contoh rekomendasi dari ITU Some examples of recommendations from the ITU

Rekomendasi CCITT antara lain, X>25, V.21, dan sebagainya, hanya rekomendasi I100 dengan I400 yang di setujui Majelis Umum pada tahun 1984 (Bagian I-IV) , rekomendasi I500-I600 dijadwalkan untuk disetujui pada tahun 1988. CCITT recommendations, among others, X> 25, V.21, and so on, only the recommendation of I100 to I400 the General Assembly approved in 1984 (Part I-IV), I500-I600 recommendations is scheduled for approval in 1988.

3. ANSI (The American Standards Institute) ANSI (The American Standards Institute)


o ANSI C12.18-1996 Protocol Specification for ANSI Type 2 Optical Port C12.18-1996 ANSI Protokol Spesifikasi untuk ANSI tipe 2 Optical Port ANSI C12.18-1996 Protocol Specification for ANSI Type 2 Optical Port ANSI C12.18-1996 Protocol Specification for ANSI Type 2 Optical Port

This standard is a very simple transport protocol, (layers 1 though 7) designed to transport data structures as defined in C12.19 via the infra-red optical port currently in use by most North American electricity revenue meters. This standard is a very simple transport protocol, (layers 1 though 7) designed to transport data structures as defined in C12.19 via the infra-red optical port currently in use by most North American electricity revenue meters. Standar ini yang sangat sederhana protokol transport, (lapisan 1 meskipun 7) dirancang untuk mengangkut struktur data sebagaimana ditetapkan dalam C12.19 melalui optik infra-merah port yang sedang digunakan oleh sebagian besar pendapatan listrik Amerika Utara meter. This standard is a very simple transport protocol, (layers 1 though 7) designed to transport the data structure as defined in C12.19 through infra-red optical port being used by most North American electricity revenue meters.

o ANSI C12.19-1997 Utility Industry End Device Tables C12.19-1997 ANSI Industri Utility Akhir Device Tabel ANSI C12.19-1997 Utility Industry End Device Tables ANSI C12.19-1997 Utility Industry End Device Tables

This standard defines a set of flexible data structures for use in metering products. This standard defines a set of flexible data structures for use in metering products. Standar ini mendefinisikan satu set struktur data yang fleksibel untuk digunakan dalam produk metering. This standard defines a set of flexible data structures for use in metering products. The standard also defines a Pascal-like syntax for identifying and describing these structures. The standard also defines a Pascal-like syntax for Identifying and describing these structures. Standar juga mendefinisikan Pascal-seperti sintaks untuk mengidentifikasi dan mendeskripsikan struktur ini. Standard also defines Pascal-like syntax to identify and describe these structures. In order to support innovation the standard also allows for inclusion of manufacturer defined tables, which may also be described in this same syntax. In order to support innovation the standard also allows for inclusion of manufacturer defined tables, which may also be described in this same syntax. Dalam rangka mendukung standar inovasi juga memungkinkan untuk dimasukkan ke tabel didefinisikan pabrikan, yang mungkin juga akan dijelaskan dalam sintaks yang sama. In order to support innovation standard also allows for inclusion into the table defined by the manufacturer, which may also be explained in the same syntax.

o ANSI C12.21-1998 Protocol Specification for Telephone Modem Communication ANSI C12.21-1998 Spesifikasi Protokol untuk Telepon Modem Komunikasi ANSI C12.21-1998 Protocol Specification for Telephone Modem Communication ANSI C12.21-1998 Protocol Specification for Telephone Modem Communication

This standard extends C12.18 and C12.19 to accommodate modem communications at the meter. This extends the standard C12.18 and C12.19 to accommodate the modem communications at the meter. Standar ini meluas C12.18 dan modem C12.19 untuk mengakomodasi komunikasi di meteran. This extends the standard C12.18 and C12.19 to accommodate modem communications at the meter.

o ANSI C12.22 - Protocol Specification for Interfacing to Data Communications Networks ANSI C12.22 - Protokol Spesifikasi untuk Interfacing Komunikasi Data Networks ANSI C12.22 - Protocol Specification for Interfacing to Data Communications Networks ANSI C12.22 - Protocol Specification for Interfacing Data Communication Networks

This working draft for a standard extends C12.18 and C12.19 to support data network communications at the meter. This working draft for a standard extends C12.18 and C12.19 to support data communications network at the meter. Rancangan kerja ini untuk memperluas standar C12.18 dan C12.19 untuk mendukung jaringan data komunikasi di meteran. The design of this work to expand C12.18 and C12.19 standards to support data communication networks in the meter. This work is currently advancing under the joint work of NEMA/ANSI, AMRA/IEEE and Measurement Canada. This work is currently advancing under the joint work of NEMA / ANSI, Amra / IEEE and Measurement Canada. Karya ini saat ini maju di bawah karya bersama NEMA / ANSI, Amra / IEEE dan Pengukuran Kanada. This work is currently under progress with the work of NEMA / ANSI, Amra / IEEE and Measurement Canada.

4. IEEE (The Institute of Electrical and Electronics Engineer) IEEE (The Institute of Electrical and Electronics Engineer)

IEEE adalah badan professional yang tekenal karena karyanya dalam mempersiapkan standar untuk antar muka, rekayasa perangkat lunak, dan yang paling berharga yaitu jaringan wilayah local (LAN, Local Area Network). IEEE is the professional body which tekenal for his work in preparing for the standard interface, software engineering, and the most precious of local area network (LAN, Local Area Network). Standar draft IEEE biasanya diratifikasi oleh ANSI sebelum diajukan ke ISO untuk ratifikasi internasional IEEE draft standard was ratified by ANSI typically prior to submission to ISO for ratification of international

Beberapa contoh standardisasi IEEE dalam transfer data Some examples of IEEE standardization in data transfer

* IEEE 802.3 — Ethernet akses LAN. IEEE 802.3 - Ethernet LAN access.
* IEEE 802.11 — Wifi, akses wireless LAN. IEEE 802.11 - WiFi, wireless LAN access.
* IEEE 802.16 — WiMAX, akses wireless MAN. IEEE 802.16 - WiMAX, wireless access MAN.

5. EIA (The Electronic Industries Association) EIA (The Electronic Industries Association)

Adalah organisasi perusahaan elektronik nasiona Amerika Serikat dan anggota asosiasi dagang ANSI. Is an organization of electronics companies nasiona United States and members of trade associations ANSI. Komite TR30 bertanggung jawab untuk pengembangan dan perawatan standart industri untuk antar muka antara peralatan pemrosesan data dan komunikasi data. TR30 Committee is responsible for the development and maintenance for industry standard interface between data processing equipment and data communications. Ini termasuk antarmuka 1 lapis – antarmuka antara mesin pengguna dengan modem, konverter sinyal, kualitas pada antar muka, dan kecepatan pen sinyalan. This includes the interface layer 1 - the interface between the user machine with a modem, a signal converter, the interface quality, and speed sinyalan pen. Komite ini bertanggung jawab untuk pengembangan antarmuka RS – 232-C EIA standar industri EIA sekarang (ini mirip dengan antar muka V.24. Standar CCITT). This Committee is responsible for the development of the interface RS - 232-C EIA EIA industry standard now (this is similar to V.24 interface. Standard CCITT). Komite TR30 disajikan dalam subkomite ANSI X3SC dalam transmisi data. TR30 Committee subcommittee presented in ANSI X3SC in data transmission.

Example standart EIA : Standard TIA 568A-B Sample EIA standard: Standard TIA 568A-B

TRANSMISSION LINES INTRODUCTION

Transmission line is used extensively in
channel high-frequency energy from a point to
Another point with the distance (usually) far enough.
Energy can be channeled through the air, cable
copper, non-copper cable, fiber optic cable and
another. One example of this function is
energy acceptance of the broadcast transmitter (transmitter
) To the transmitter antenna.
Ideally, the distributed energy should not
experience attenuation, disability (changing forms) and free
noise.
In reality these ideal conditions have not
can be realized, although today there are material
superconductors can be operated but not in
realistic temperature (near room temperature).
Low frequency (60 Hz) that the
transmitted through the netting PLN is not a
example of the transmission line that we're talking about. If
we see based on the transmission line cross-sectional area
(non-air).

Source : State polytechnic of Malang

Understanding Telecommunications

Telecommunications composed of two letters, telephone and communications, tele meaning remote, and communication means relationships, can be interpreted as long-distance communication.
Telecommunication is transmission of signals over a distance for the purpose of communication. In earlier times, this may have involved the use of smoke signals, drums, semaphore, flags or heliograph. In modern times, telecommunication typically involves the use of electronic devices such as the telephone, television, radio or computer. Early inventors in the field of telecommunication include Alexander Graham Bell, Guglielmo Marconi and John Logie Baird. Telecommunication is an important part of the world economy and the telecommunication industry's revenue was estimated to be $1.2 trillion in 2006.

Source : wikipedia.org/wiki/Telecommunication