Need help! I2c data bus with pic 16f84a

hi to all
I have a simple micro controller project. It's an intelligent switch based on lighting systems. I need to read the status in another light in same i2c data bus.
It has 21 switches (with one bulb in each switch).
The main task is the switch should be able to control our bulb and others bulbs by using a switch.
That's why i need to read the status of another switch and control it. I know i2c is a simple method to do it.
My question is "How can use i2c data bus with pic 16f84a?" . Do i need a A/D converter?
If you have asm file which shows the instruction it will very useful to me!!!!!!!!!
Regards

Please forgive me for side-stepping your question.

If there's a substantial distance between switch devices you might want to consider serial I/O between devices with RS485 driver ICs on each device. The RS485 signals are relatively immune to noise and can cover some very decent distances

You can implement bit-banged serial I/O on the 'F84 but I would strongly recommend upgrading to another more modern PIC which has a hardware serial port built-in.

Heh, I guess your not familiar with I2C at all, or uProcessors?


Dallas has a range of 1-Wire products that includes switches. I'm not sure of a supplier for them though