Port

Parallel Port:

1. Type A – DV25 Port. 25 pin
2. Type B – Centronics Connector . 36 pin.
3. Type C – Mini connector. 36 pin


Communication Method
Communication Method are of two types:

1. Serial Communication ------ 1-0-1-1-1-1-1-1
2. Parallel Communication ----- 1-1
0-0
1-1
1-1

Serial Communication are of two types:

1. Synchronous – Total data at a time as a Frame. Router use this method.
2. Asynchronous – Single character at a time, by different channel & different signal. 1 channel - 1 bit. Modem device use this method.

Computer’s support Parallel Communication. Data receive by computer parallely, but after receive by port it become Serial.

What is Hand Shaking?
When two modem establish communication with each other then its called hand-Shaking.

How Modem Work?
Modem works on bps.

What is Modulation And Demodulation?

What is Frequency?
Frequency means Wave. Like device man has frequency also. As - Frequency of brain which called Telepathy.

Wireless Connection:
Wireless Connection can be of 3 types:
1. Infrared: Infrared works by Ray.
2. Radio Frequency: It has no limitation, it can connect device to device device to man.
Blue tooth : Same as like Radio Frequency but by default it is limited. It can connect device to device

What is ROM?

Rom is non-volatile Memory. Its about 4 kinds:

1. ROM (Read-only Memory) - It’s a chip which can’t be altered. Technically, its called Masked ROM Chip.
2. PROM (Progammable Read-only Memory) - It’s a blank Rom chip, which is burned on a special kind of Rom Burner. In this chip the instruction remain burn, Later which can’t be changed, update and add.
3. EPROM (Erasable Programmable Read-only Memory) – Its like as PROM, but a square crystal reside on its top, by which data can be erased. UV Light is used to change the binary data of EPROM to its original state.After erasing the data, by using Rom Writer, data can be write again on EPROM
4.EEPROM (Electrically Erasable Programmable Read only Memory) – Its called flash ROM also. It’s a chip which can be reprogram by BIOS/Chip Manufacturer, they ues software to do this. This process is called Flashing.
To reprogramm EEPROM we don’t need to remove this from the system. Like – PenDrive & BIOS which can electrically read, write and delete data.

Difference between the EEPROM of Pendrive & Bios
Pendrive & BIOS both can electrically read, write and delete data, but pen drive’s EEPROM is not CIMOS, BIOS’s EEPROM is CIMOS.


What is Propritery?
Many notebook use Proprietery formats for their Memory Modules. Then to upgrade or replace RAM, we need to upgrade or replace the RAM from the company who has the propritery of the RAM.