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Howto Block a Port in Squid Proxy , Ubuntu Linux

Here I show a small Squid Access Control technique for blocking a port for all users and open it for a selected user.

Open /etc/squid/squid.conf file by using
# vi /etc/squid/squid.conf

Locate your Access Control List (ACL) section and add configuration directive as shown below:

acl block_ port port 5050
http_access deny block_port
http_access allow all

The above directives will help you to block port 5050

If you wish to allow the above blocked port to a particular IP (192.168.0.101) try as follows:

acl block_port port 1234
acl no_block_port_ip src 192.168.0.101
http_access deny block_port !no_block_port_ip
http_access allow all

Save and Close the file

Restart squid proxy by using
# /etc/init.d/squid restart

Getting started with Arduino

Here You can see a very good site for Arduino Open Hardware Starting

Chapter Zero
Chapter One
Chapter Two
Chapter Three
Chapter Four
Chapter Five
Chapter Six
Chapter Six Added
ChapterSeven
Chapter Eight

Get your free Subscription : Electronics Design

Electronics Design is a great book for Electronics Engineers. It is also useful for Electronivcs Students and teachers. Digital and printed copy are freely Available. It Serves the technical information needs of electronic engineers and engineering managers responsible for the design and development of EOEM products and systems.

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Download Proteus 7.6 sp4

I have seen a download link for Proteus 7.6 sp4. Thanks for sharing
Proteus is a very good software for electronics simulation and PCB design
If you like this software please purchase a Licensed copy
http://depositfiles.com/files/q1kzk3gie

How to Interface PIC16F877A / 18F452 with RS232C Serial Communication Using CCSC

Communication between a Microcontroller and a Computer is not a big thing. Use a level converter in between Microcontroller and PC. You can test it using a proteus simulation  or directly connect your hardware to PC and use Hiper Terminal for Testing

Here a Simple code for testing Serial Communication

        #include <16F877A.h>
        #DEVICE ADC=10
        #fuses HS,NOWDT,NOPROTECT,NOLVP
        #use delay(clock=20000000)
        #use rs232 (baud=9600,rcv=PIN_C7, xmit=PIN_C6)

        int count=0;
      
        void main()
        {
        while(1){

        //1 Sec Delay
        delay_ms(1000);

        //Increment Count
        count ++;
        if (count>60)
      {  count=0;}

        //Send data to PC
        printf("\n\r Count Value: %d",count);
        }
        }

LED Operates Directly From AC

Acriche is the world’s first semiconductor light source that operates directly from AC power without a converter. This makes it suitable for many residential and commercial lighting applications where the main source of available power is AC.

Operates on AC power without additional conversion circuitry

Operating Voltage: 100V, 110V, 220V, 230V

Long Life: over 35,000 hours

No converter loss = higher fixture efficacy

Operating frequency: 50/60 Hz

Available in warm white and pure white

Multiple package options

See Link