RS232 Serial Communication - PUJARKN/Black-n-White GitHub Wiki

#Standared is serial communication used to communicate between Data Terminal equipment and Data communication Equipment

RS232 can be configured in three different modes.

  1. All DB9 Pins need to have Hardware Hand shake. ( Earlier days )
  2. HW +SW Handshaking by sending X-On and X_off. ( Which are in ASCII Table as DC1 and DC3)
  3. SW Handshaking. ( Presently used )

We ought to consider the Electrical as well as mechanical specification of RS232 Standard.

Electrical Specification

  1. Rise and Fall Time
  2. Cable Types
  3. Bipolar Logic i. Logic 1 => 0 V to +12 V ii. Logic 0 => 0 V to - 12V
  4. Current levels

Mechanical Specification

  1. There are two ways to connect i. Modem ( connect the DB9 to Modem ) ii. Non-Modem ( Directly connect the DB9 to DB9 without in between modem)

Note 🥇 : It is always recommended that use MAX232 IC for step up voltage from 5 V to 12 V. If you happen to use Transistor or any other circuit to step up voltage ,certainly, It will work for small distance but for longer distance it will definitely fail. It is also considered as out of standard of RS232.