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     The Interesting Technology Blog

This is a blog I have running called Interesting technology, just because it's quicker to add interesting stuff as it comes across my desk to a blog than editing a static website..  

 Linked to the Interesting Technology Blog are several pages where you can get the latest:

 Antivirus, spyware and registry tools

Web site and domain tools products

Online PC software Products

Green energy and Science Products


 

        RSS Feed from the Interesting Tech Blog

              Antique Electronics

         There are many Electron Tube suppliers still available today

Sets made before the early 1920s, when public broadcasting commenced, are rarely seen, so most "old" radios found were made between 1925 and the late 1960s. Listed here are some of the clues to dating old radios.

  • 1920 - 1929

    Radios of this period were mainly of the wooden "coffin" type with a hinged lid at the top and controls at the front, with any frequency indication being 0-100 markings on the large tuning knobs. Components were mounted on a wooden base board and the front panel, usually of black ebonite. Many were homemade and have no makers information. Bigger sets had several tuning stages, each with its own knob, which made them hard to tune.

     

  • 1930 - 1934

    During this period most radios were built into large well made wooden cabinets, often floor standing with access to the works from the back. Dials were small with 0-100 markings, with a single tuning knob and components attached to a metal removable chassis which contained the valves and large components on top, with the wiring and smaller parts underneath. Only the AM broadcast band was covered.

     

  • 1935 - 1939

    The later 1930s saw larger circular dials with a central pointer, often with stations marked, and sometimes with the addition of short wave bands. As well as wooden sets, some table or mantel cabinets were now made from attractive Bakelite mouldings usually in a dark brown or cream colour. The chassis types were similar but with smaller components while 8-pin octal valves became standard over this period. Radiograms were introduced, remaining popular until the 1960s.

    From 1934 until the 1960s nearly all Australian sets had a transfer, usually in blue, labelled ARTS&P on the back of the metal chassis to cover patent licensing. The letter preceding the serial number can give a guide to the year made. From 1934 to 1941 the letters A-F were used, with G-I, or no letter, being postwar.

     

  • 1940 - 1949

    Few domestic radios were made during WWII but radios of the late 1940s were often similar in size and style to the late 1930s. Miniature valves, introduced during the war, became available and were used initially in the manufacture of small Bakelite portable sets. Mains sets now had On/Off switches, usually combined with the volume control.

     

  • 1950 - 1959

    This decade saw the full introduction of the miniature type of valve and plastic cases gradually replaced Bakelite, allowing the introduction of brighter coloured sets. Car and portable radios also became more popular. Towards the end of the period, the first transistor sets came on to the market, usually as portables.

     

  • 1960 - 1969

    Australian radio manufacturing was superseded by imports towards the end of this period and solid state sets became universal. Station identification on dials fell out of use and FM bands were available on some imported receivers, though no such stations existed here until the 1970s. Size reduction meant that most receivers were plastic cased and portable by the end of the period. Radiograms were superseded by component stereo systems.

     


  • Clickbank Products

    Activities For Radio Hobbyists

    Amateur radio or ham is largely a hobby activity. The majority of their hobby time is spent on making contact and having conversations with people in distant regions and from different cultures. Two way communications, identifying their location and station, zone, region and place is the usual custom. This is always followed by other casual communications. If the contact is made for a contest to make two way communication with as many stations or ham radio operators as possible, this all the information that is shared.

    DX-ing and DX-peditions: An amateur radio operator's main hobby is to make contact with as many stations as possible from as many parts of the world as possible. DX stands for Distant Stations. The DX-ing usually is followed with the QSO. (a Q code., see below) which means "a conversation".

    DX-peditions are different in the sense that they are expeditions organized / planned solely for the purpose of making contacts with some special or rare stations and regions. Some people travel long distance just to make contact with some unrepresented region or place.

    Radio Frequency scanners available now a days form the tool of great use in these attempts. The radio scanner scans for signals until a strong signal is found.

    QSL cards: The Q code is a standardized collection of three-letter message encodings, all starting with the letter "Q", initially developed for commercial radiotelegraph communication, and later adopted by other radio services, especially amateur radio. In today's audio signal transmission age, the Q codes are not essential. but still in use and are viewed as a sort of tradition.

    As a part of DX-ing and DX-peditions the QSL card or the proof of contact card is shared. QSL is one such Q-code that means "I acknowledge receipt". The common practice was that the ones who made contact at a particular frequency exchange a QSL card in the mail to confirm their contact and conversations. These QSL cards can be used as a proof of their making contact and amateur operators who make contact with a certain number of other amateur radio operators in a specified time is awarded. Moreover, they are distinguished and honored since they are deemed to be efficient amateur radio operators.

    Remote region contacting: Some countries have less amateur radio operators, and making contact with these is considered special. So, when a radio amateur from these regions makes contact, other ham operators flock to make communication with this / these hams. Making contact with these less represented places has its awards and special considerations in the award programs.


    Hamfests are Social events for the ham families and friends. It's something akin to the family oriented social fests where there are sales, exchanges, meetings and fun. Similarly, the fest is filled with selling and exchanging hams, meeting real life ham friends and fun events for a day or sometimes over few days.

    Discussion groups and Nets: Ham operators form a discussion group based on common interests other than ham or it can also be a ham related discussion group and they can form nets or networks.

    If a radio hobbyist gets involved with all of these different activities, he or she is sure to never be bored. Look into some of them, and see if you would like to get involved. 

     

    Q Codes Commonly Used by Radio Amateurs

    Code Question Answer or Statement
    QRA What is the name (or call sign) of your station? The name (or call sign) of my station is ...
    QRG Will you tell me my exact frequency (or that of ...)? Your exact frequency (or that of ... ) is ... kHz (or MHz).
    QRI How is the tone of my transmission? The tone of your transmission is (1. Good; 2. Variable; 3. Bad)
    QRK What is the readability of my signals (or those of ...)? The readability of your signals (or those of ...) is ... (1 to 5).
    QRL Are you busy? I am busy. (or I am busy with ... ) Please do not interfere.
    QRM Do you have interference? I have interference.
    QRN Are you troubled by static? I am troubled by static.
    QRO Shall I increase power? Increase power
    QRP Shall I decrease power? Decrease power
    QRQ Shall I send faster? Send faster (... wpm)
    QRS Shall I send slower? Send slower (... wpm)
    QRT Shall I stop sending? Stop sending.
    QRU Have you anything for me? I have nothing for you.
    QRV Are you ready? I am ready.
    QRX When will you call me again? I will call you again at ... (hours) on ... kHz (or MHz)
    QRZ Who is calling me? You are being called by ... on ... kHz (or MHz)
    QSA What is the strength of my signals (or those of ... )? The strength of your signals (or those of ...) is ... (1 to 5).
    QSB Are my signals fading? Your signals are fading.
    QSD Is my keying defective? Your keying is defective.
    QSK Can you hear me between your signals? I can hear you between my signals.
    QSL Can you acknowledge receipt? I am acknowledging receipt.
    QSM Shall I repeat the last telegram (message) which I sent you, or some previous telegram (message)? Repeat the last telegram (message) which you sent me (or telegram(s) (message(s)) numbers(s) ...).
    QSN Did you hear me (or ... (call sign)) on .. kHz (or MHz)? I did hear you (or ... (call sign)) on ... kHz (or MHz).
    QSO Can you communicate with ... direct or by relay? I can communicate with ... direct (or by relay through ...).
    QSR Do you want me to repeat my call? Please repeat your call; I did not hear you.
    QSU Shall I send or reply on this frequency (or on ... kHz (or MHz))? Send or reply on this frequency (or on ... kHz (or MHz)).
    QSW Will you send on this frequency (or on ... kHz (or MHz))? I am going to send on this frequency (or on ... kHz (or MHz)).
    QSX Will you listen to ... (call sign(s) on ... kHz (or MHz))? I am listening to ... (call sign(s) on ... kHz (or MHz))
    QSY Shall I change to transmission on another frequency? Change to transmission on another frequency (or on ... kHz (or MHz)).
    QTA Shall I cancel telegram (message) No. ... as if it had not been sent? Cancel telegram (message) No. ... as if it had not been sent.
    QTC How many telegrams (messages) have you to send? I have ... telegrams (messages) for you (or for ...).
    QTH What is your position in latitude and longitude (or according to any other indication)? My position is ... latitude...longitude
    QTR What is the correct time? The correct time is ... hours

     

                  3 Valve Receiver Circuits

    The Book Below contains 5 circuits and construction techniques for

    3 valve receivers.

                 4 Valve Receiver Circuits

    The Book Below contains Circuits and construction techniques for

    4 valve receivers.

                     Binary to Text (ASCII) Conversion

     

    Ever want to send an encoded message that only a handful of people can actually crack the code?

    This shweet conversion tool will take any text string and convert it into binary code - you know? those little 1's and 0's that make our world go around today... the digital world.

    So go ahead, send some coded messages.... That's right! Send a message to friend in digital format and all they have to do is come back here, plug it in to the binary field and Voila!

     Here's a little message from me to you.

    010101000110100001100001011011100
    110101101110011001000000110011001
    101111011100100010000001110110011
    010010111001101101001011101000110
    100101101110011001110010000001001
    100011010010110011001100101001000
    000110100101110011001000000110000
    101101110001000000100000101100100
    011101100110010101101110011101000
    11101010111001001100101

     

    Tables for ASCII and binary characters (the characters)

     

                          Electricity onboard.

     

    There are many common misconceptions regrading battery capacity.

    Deep cycle batteries are sold by capacity and are normally rated in amp-hours (Ah). It would be reasonable to expect a 100 amp hour battery to deliver one hundred amp hours – one amp for one hundred hours OR ten amps for ten hours.

    Sadly this a long way from the truth. The number of amp hours you can extract from a given battery is dependent on the following factors:

    The battery’s chemistry – for example – common lead acid batteries will deliver far less energy than AGM or GEL batteries for the same amp hour rating.
    The batteries age – as batteries age they become less able to deliver the same capacity.
    Your willingness to shorten the life of the batteries by deeply discharging the battery.
    The chargers ability to fully charge the battery.

    The following link goes to an online PDF from Victron Energy.

    It's a must read as it describes all the different types of batteries and charging methods available for Yachts but this information and formula is equally applicable to any domestic application you may have.

    It has chapters on why batteries fail and how to make them last longer, alternators and generators, power calculations and much more.

    I won't reproduce the Victron report here for copy-write reasons, but click the link to check it out, A good read IMHO.


    http://www.planet-energy.org/sustainable_energy/ebooks/ElectricityonBoard_rev8_july2004.pdf

     

    Tubes on youtube..

                     Some facts to ponder on

    200 hours of video was uploaded every minute since the Japanese earthquake (mostly of the disaster and its aftermath).

    By the year 2013, 80 - 90% of all internet (IP) network traffic will be video traffic.

    Video will quadruple IP traffic by 2014 (to 767 *Exabytes per year). See *below

    By the end of 2011 the will be 3.6 billion mobile network devices on the internet.

    7 Billion new wireless devices will be ADDED by 2015. That is more than what the population of the world will be by then. That means more than wireless device one per living person (of all ages).

    300,000 Android devices are added to the internet per day.

    Android is the 2nd biggest mobile platform in the world (2 years earlier than expected), it is the largest platform in the USA. In 2 years time, will be the biggest mobile platform in the world.

    By the year 2020 storage requirements will increase 44 fold. (NB, not 44%)

    The iPad and the Apple Mac = 12% of the world’s wireless population.


    Corporate Instant Messaging (IM) will be the next big thing – Yahoo, Gmail, Mixit, Twitter, Facebook, You tube, E-Blogger, Linked-in Cisco Jabber and other social media.

    Warning to Businesses: IGNORE SOCIAL MEDIA AT YOUR OWN PERIL.

    Facebook offers over 500,000 applications.

    Borderless networks means business will have to give access to – ANYONE, ANYTIME, on ANYTHING (device type) and from ANYWHERE. This is for staff and customer communication.

    55% of all electrical power in the IT sphere is used outside the Data Centre, in branches and areas of presence (PCs, switches, printers, mobiles and other devices)

    The use of Unified messaging (such as Cisco Jabber) will dominate communication (Voice / video) over the internet instead of expensive Cellphone airtime. You will be able to switch seamlessly between your desk phone (IP), your mobile, your laptop or your iPad, even during a call (for instance, when you have to leave the office, get into your car to drive somewhere).

    Cisco saved 90 million US dollars in one year by banning staff business travel and they had to use video conferencing instead.

    Cisco’s last sales conference (CSX) was “attended” by 23 000 sales staff via video conferencing from all over the world.


    *Just to be clear:

    There are three definitions of megabyte (MB), two of which are commonly used in computing:

    1000 × 1000 = 1,000,000 bytes in a megabyte - Most commonly used. This is the standard SI definition, used for most media measurements (like hard drives and DVDs), for networking, and in some software (like Mac OS X and Linux).

    1024 × 1024 = 1,048,576 bytes in a megabyte - This is the definition commonly used by memory manufacturers and in some software (like Microsoft Windows). The official term for this unit is "mebibyte" (MiB).

    1024 × 1000 = 1,024,000 bytes in a megabyte - This definition was used in the once-common "1.44 MB" floppy disk


    1 000 bytes = 1 Kilobyte (103) abbr KB
    1 000 000 bytes = 1 Megabyte (106) abbr MB

    1 000 000 000 bytes = 1 Gigabyte (109) abbr GB

    1 000 000 000 000 bytes = 1 Terabyte (1012) abbr TB

    1 000 000 000 000 000 bytes = 1 Petabyte (1015) abbr PB

    1 000 000 000 000 000 000 bytes = 1 Exabyte (1018) abbr EB

    1 000 000 000 000 000 000 000 bytes = 1 Zettabyte (1021) abbr ZB

    1 000 000 000 000 000 000 000 000 bytes = 1 Yottabyte (1024) abbr YB

    From here on it is the proposed (but not official as far as I know) system. However, Yotta is the second last Greek alphabet letter - the last letter would be the Omega.

    It could be that the next one would be the Omegabyte. After they run out of options with the Greek alphabet, they could go to something else, like Egyptian or some other ancient alphabet.

    1 000 000 000 000 000 000 000 000 000 bytes = 1 Xonabyte (1027) abbr XB
    1 000 000 000 000 000 000 000 000 000 000 bytes = 1 Wekabyte (1030) abbr WB

    1 000 000 000 000 000 000 000 000 000 000 000 bytes = 1 Vundabyte (1033) abbr VB

    1 000 000 000 000 000 000 000 000 000 000 000 000 bytes = 1 Udabyte (1036) abbr UB

    1 000 000 000 000 000 000 000 000 000 000 000 000 000 bytes = 1 Tredabyte (1039) abbr TDB

    1 000 000 000 000 000 000 000 000 000 000 000 000 000 000 bytes = 1 Sortabyte (1042) abbr SB

    1 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 bytes = 1 Rintabyte (1045) abbr RB
    1 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 bytes = 1 Quexabyte (1048) abbr QB
    1 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 bytes = 1 Peptabyte (1051) abbr PPB
    1 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 bytes = 1 Ochabyte (1054) abbr OB

    1 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 bytes = 1 Nenabyte (1057) abbr NB
    1 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 bytes = 1 Mingabyte (1060) abbr MIB
    1 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 bytes = 1 Lumabyte (1063) abbr LB

    Will we ever get there?

             Advertising from BannersGoMLM...

          Basic RADAR principles

      I am currently typing out my notes from when I was working on RADAR gear, hopefully you will find it interesting - there is a bit of "smoke and mirrors" involved with this theory but still good brain exercise :-)

    How RADAR works – Part 1

    This is written as a basic introductory of how RADAR systems work and outlines general principles involved with this equipment.

    PRINCIPLES OF RADAR

    What is RADAR?

    RADAR stands for Radio Detection And Ranging

    Types of RADAR:

    PULSE MODULATED SYSTEM

    The radiation from the Transmitter (TX) is in the form of very short duration pulses, followed by a relatively long period in which the TX is switched off and the receiver is operative.

    CW RADAR

    This type of RADAR relies on the “Doppler shift” in frequency of the CARRIER WAVE to detect moving objects and to measure their speed.

    FM CW RADAR

    Frequency Modulated CW RADAR measures the difference in Frequency between the reflected wave from the Target and the direct wave from the transmitter.

     For Full document Part 1 click here

    Part 2 and part 3 have also been added.

     


    Clickbank Products

           Latest Updates from Cisco Systems.

    What is RSS?

    Really Simple Syndication (RSS) is an XML-based format for distributing and aggregating Web content (such as news headlines).Using RSS, web content providers can easily create and disseminate news headlines and URLs.

    Typical applications for using RSS feeds include using a program known as a News Aggregator (also called news reader) to collect, update and display RSS feeds on another webpage. You simply plug in the addresses of the RSS files you want. By using RSS feeds, website owners can keep websites 'fresh' and up to date.

    Another way many people use RSS feeds is by incorporating content into weblogs, or "blogs". Blogs are a publishing tool used for many purposes and consist of web pages comprised of usually short, frequently updated items and web links.  

     

     Below is the latest Security Notices from Cisco and partners.

     

     Below is the Latest Field Notices from Cisco systems


    Do It Yourself- Mobile Phone Repair Course

     

     

    This course is a home study  type course to easily learn mobile phone repairing. This course is suitable for all people. After completing the course you will be able to repair minor as well as major handset faults.

    Do It Yourself- Mobile Phone Repair Course:

    Excellent savings from Microsoft.

    Currently, the Microsoft Store already offers over 300 Microsoft consumer products for sale and will offer a full selection of Microsoft products in the coming months. These flagship products include the following:


    • Microsoft Office 2010- Home and Student Editions
    • Windows 7 software (both boxed and downloadable versions)
    • Office software (boxed and downloadable)
    • Xbox consoles + Xbox Kinect accessories and games
    • PC hardware such as keyboards and mice
    • PC games
    • Zunes
    • Other MS software products such as Expression, Visual Studio and Works


    Current offers:


    • $10 off Microsoft Life Cam! Only $39.95!
    • $10 off Xbox 360 GB console + Xbox LIVE 12 Month Card from the Microsoft Store!
    • Free shipping on all Xbox Consoles and PCs from the Microsoft Store!

    SUBNETTING

    SUBNETTING is a very important part of networking - my job :-)

     

    Subnet Chart

    CIDR      Subnet Mask       Addresses         Wildcard

    /32         255.255.255.255           1                      0.0.0.0

    /31         255.255.255.254           2                      0.0.0.1

    /30         255.255.255.252           4                      0.0.0.3

    /29         255.255.255.248           8                      0.0.0.7

    /28         255.255.255.240          16                     0.0.0.15

    /27         255.255.255.224           32                    0.0.0.31

    /26         255.255.255.192           64                    0.0.0.63

    /25         255.255.255.128          128                   0.0.0.127

    /24         255.255.255.0               256                   0.0.0.255

    /23         255.255.254.0               512                   0.0.1.255

    /22         255.255.252.0              1,024                 0.0.3.255

    /21         255.255.248.0              2,048                 0.0.7.255

    /20         255.255.240.0              4,096                 0.0.15.255

    /19         255.255.224.0              8,192                 0.0.31.255

    /18         255.255.192.0             16,384                0.0.63.255

    /17         255.255.128.0              32,768               0.0.127.255

    /16         255.255.0.0                  65,536                0.0.255.255

    /15         255.254.0.0                 131,072               0.1.255.255

    /14         255.252.0.0                 262,144               0.3.255.255

    /13         255.248.0.0                 524,288               0.7.255.255

    /12         255.240.0.0              1,048,576               0.15.255.255

    /11         255.224.0.0              2,097,152               0.31.255.255

    /10         255.192.0.0             4,194,304                0.63.255.255

    /9           255.128.0.0             8,388,608                0.127.255.255

    /8           255.0.0.0               16,777,216                0.255.255.255

    /7           254.0.0.0                33,554,432               1.255.255.255

    /6           252.0.0.0                67,108,864                3.255.255.255

    /5           248.0.0.0              134,217,728                7.255.255.255

    /4           240.0.0.0               268,435,456               15.255.255.255

    /3           224.0.0.0               536,870,912                31.255.255.255

    /2          192.0.0.0              1,073,741,824              63.255.255.255

    /1          128.0.0.0               2,147,483,648             127.255.255.255

    /0           0.0.0.0                  4,294,967,296              255.255.255.255

     

    Decimal to Binary

    Subnet Mask

    255 1111 1111

    254 1111 1110

    252 1111 1100

    248 1111 1000

    240 1111 0000

    224 1110 0000

    192 1100 0000

    128 1000 0000

    0 0000 0000

    Wildcard

    0 0000 0000

    1 0000 0001

    3 0000 0011

    7 0000 0111

    15 0000 1111

    31 0001 1111

    63 0011 1111

    127 0111 1111

    255 1111 1111

    Subnet Proportion

    Classful Ranges

    A 0.0.0.0 - 127.255.255.255

    B 128.0.0.0 - 191.255.255.255

    C 192.0.0.0 - 223.255.255.255

    D 224.0.0.0 - 239.255.255.255

    E 240.0.0.0 - 255.255.255.255

    Reserved Ranges

    RFC1918 10.0.0.0 - 10.255.255.255

    Localhost 127.0.0.0 - 127.255.255.255

    RFC1918 172.16.0.0 - 172.31.255.255

    RFC1918 192.168.0.0 - 192.168.255.255

    Determine Usable Hosts

    Total Addresses

    - Subnet ID

    - Broadcast Address

    Usable hosts

    256

    - 1

    - 1

    254

    Terminology

    CIDR · Classless interdomain routing was developed to

    provide more granularity than legacy classful addressing;

    masks expressed in the form /XX are in CIDR notation

    VLSM · Variable length subnet masks are an arbitrary length

    between 0 and 32 bits; CIDR relies on VLSMs to define routes

     


    IPV6 Information

    IPV6 is the new ageof networking

    Protocol Header

    Version (4 bits) · Always set to 6

    Traffic Class (8 bits) · A DSCP value for QoS

    Flow Label (20 bits) · Identifies unique flows (optional)

    Payload Length (16 bits) · Length of the payload in bytes

    Next Header (8 bits) · Header or protocol which follows

    Hop Limit (8 bits) · Functions as IPv4's time to live field

    Source Address (128 bits) · Source IP address

    Destination Address (128 bits) · Destination IP address

    Address Types

    Unicast · One-to-one communication

    Multicast · One-to-many communication

    Anycast · An address configured in multiple locations

    Address Notation

    Step 1 · Eliminate all leading zeros

    Step 2 · Replace up to one set of consecutive zeros with a

    double-colon

    Address Formats

    Global unicast

    Link-local unicast

    Multicast

    EUI-64 Formation

    Step 1 · Insert 0xfffe between the two halves of the MAC

    Step 2 · Flip the seventh bit (universal/local flag) to 1

    Special-Use Ranges

    ::/0 Default route

    ::/128 Unspecified

    ::1/128 Loopback

    ::/96 IPv4-compatible*

    ::FFFF:0:0/96 IPv4-mapped

    2001::/32 Teredo

    2001:DB8::/32 Documentation

    2002::/16 6to4

    FC00::/7 Unique local

    FE80::/10 Link-local unicast

    FEC0::/10 Site-local unicast*

    FF00::/8 Multicast

    * Deprecated

    Extension Headers

    Hop-by-hop Options (0) · Carries additional information which must be

    examined by every router in the path

    Routing (43) · Provides source routing functionality

    Fragment (44) · Included when a packet has been fragmented by its source

    Encapsulating Security Payload (50) · Provides payload encryption (IPsec)

    Authentication Header (51) · Provides packet authentication (IPsec)

    Destination Options (60) · Carries additional information which pertains only to

    the recipient

    Transition Methods

    Dual Stack · Running IPv4 and IPv6 on all devices simultaneously

    Tunneling · IPv6 packets are encapsulated into IPv4 using IPv6-in-IP, UDP

    (Teredo), or Intra-Site Automatic Tunnel Addressing Protocol (ISATAP)

    Translation · Stateless IP/ICMP Translation (SIIT) translates IP header fields and

    NAT Protocol Translation (NAT-PT) maps between IPv6 and IPv4 addresses

     

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       IPsec Information - general

    What is Internet Protocol Security?

    (IPsec) is a protocol suite for securing Internet Protocol (IP) communications by authenticating and encrypting each IP packet of a communication session. IPsec also includes protocols for establishing mutual authentication between agents at the beginning of the session and negotiation of cryptographic keys to be used during the session.

    IPsec is an end-to-end security scheme operating in the Internet Layer of the Internet Protocol Suite. It can be used in protecting data flows between a pair of hosts (host-to-host), between a pair of security gateways (network-to-network), or between a security gateway and a host (network-to-host).

     Protocols

    Internet Security Association and Key Management Protocol
    (ISAKMP)
    · A framework for the negotiation and management of
    security associations between peers; traverses UDP port 500


    Internet Key Exchange (IKE) · Responsible for key agreement using
    public key cryptography


    Encapsulating Security Payload (ESP) · Provides data encryption,
    data integrity, and peer authentication; IP protocol 50


    Authentication Header (AH) · Provides data integrity and peer
    authentication, but not data encryption; IP protocol 51

     

     Terminology

    Data Integrity · Secure hashing (HMAC) is used to ensure
    data has not been altered in transit


    Data Confidentiality · Encryption is used to ensure data
    cannot be intercepted by a third party


    Data Origin Authentication · Peer authentication
    Anti-replay · Sequence numbers are used to detect and
    block duplicate packets


    Hash-based Message Authentication Code (HMAC) · A
    hash of the data and secret key used to provide message
    authenticity


    Diffie-Hellman · A method of establishing a shared secret
    key over an insecure path using public and private keys

     

     Encryption Algorithms

    Type                                          Key                                           Strength
    DES Symmetric                       56-bit                                            Weak
    3DES Symmetric                  168-bit                                           Medium
    AES Symmetric           128, 192, or 256-bit                               Strong
    RSA Asymmetric            1024-bit  minimum                              Strong

    Hashing Algorithms

                      Length              Strength
    MD5          128-bit              Medium
    SHA-1      160-bit                Strong  

     Cisco Troubleshooting Commands

    show crypto isakmp sa
    show crypto isakmp policy
    show crypto ipsec sa
    show crypto ipsec transform-set
    debug crypto isakmp

    debug crypto ipsec

     

                                               Teravolt.org

    What is Electricity?



    Atoms (the stuff that makes up stuff) have a nucleus; a hard center which determines the atom's weight and properties. This nucleus is made of both positively charged protons and charge-less neutrons. Spinning around that nucleus at near the speed of light are clouds of electrons; particles with a negative charge. Normally the atoms have an identical number of electrons and protons, and because of this atoms typically have a net charge of 0. However, these electrons can be removed or added leaving the atom charged either charged positively or negatively, respectively.

     

    Lots more interesting Electronics stuff at TERAVOLT.ORG

     

    So You Want To Be An Sap Professional?

    Insider Secrets, Shortcuts And Proven Tactics To Break Into Sap, Get Good, And Earn A Great Living As An Sap Professional... Finally Revealed By Pros Who Play The Game Themselves. An Interesting E Book...

    If working and earning in IT or SAP interests you then Click Here!

    The Easy Guide To Solar And Wind Power.

    Green Power Easy Is The Easiest Guide To Solar And Wind Energy On The Planet. Convert Your Entire Home To Green Power, And Eliminate Your Power Bill! - Worth a look.

    If Alternative energy is your thing then Click Here!

     

    Tech Support for Women



    Dear Tech Support,
    Last year I upgraded from Boyfriend 5.0 to Husband 1.0 and noticed a distinct slow down in overall system performance -- particularly in the flower and jewellery applications, which operated flawlessly under Boyfriend 5.0

    In addition, Husband 1.0 uninstalled many other valuable programs, such as Romance 9.5 and Personal Attention 6.5 and then installed undesirable programs such as Football 5.0, The Ashes 3.0, and Golf Clubs 4.1.

    Conversation 8.0 no longer runs, and Housecleaning 2.6 simply crashes the system. I've tried running Nagging 5.3 to fix these problems, but to no avail!

    What can I do?
    Signed, Desperate
    ===========================================
    Dear Desperate:
    First keep in mind, Boyfriend 5.0 is an Entertainment Package, while Husband 1.0 is an Operating System.

    Please enter the command: 'http: I Thought You Loved Me.html' and try to download Tears 6.2 and don't forget to install the Guilt 3.0 update. If that application works as designed, Husband 1.0 should then automatically run the applications Jewellery 2.0 and Flowers 3.5.

    But remember, overuse of the above application can cause Husband 1.0 to default to Grumpy Silence 2.5,Happy Hour 7.0 or Beer 6.1.

    Beer 6.1 is a very bad program that will download the Snoring Loudly Beta.

    Whatever you do, DO NOT install Mother-in-law 1.0 (it runs a virus in the background that will eventually seize control of all your system resources).

    Also, do not attempt to reinstall the Boyfriend 5.0 program. These are unsupported applications and will crash Husband 1.0.

    In summary, Husband 1.0 is a great program, but it does have limited memory and cannot learn new applications quickly. You might consider buying additional software to improve memory and performance.

    We recommend Food 3.0 and Hot Lingerie 7.7.


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