RS232 Interface using MAX232 ( What is RS232 ? )

What is RS232 ?

Description :

In telecommunications, RS-232 is a standard for serial communication transmission of data. It formally defines the signals connecting between a DTE (data terminal equipment) such as a computer terminal, and a DCE (data circuit-terminating equipment or data communication equipment), such as a modem. The RS-232 standard is commonly used in computer serial ports. The standard defines the electrical characteristics and timing of signals, the meaning of signals, and the physical size and pinout of connectors. The current version of the standard is TIA-232-F Interface Between Data Terminal Equipment and Data Circuit-Terminating Equipment Employing Serial Binary Data Interchange, issued in 1997.

An RS-232 serial port was once a standard feature of a personal computer, used for connections to modems, printers, mice, data storage, uninterruptible power supplies, and other peripheral devices. However, RS-232 is hampered by low transmission speed, large voltage swing, and large standard connectors. In modern personal computers, USB has displaced RS-232 from most of its peripheral interface roles. Many computers do not come equipped with RS-232 ports and must use either an external USB-to-RS-232 converter or an internal expansion card with one or more serial ports to connect to RS-232 peripherals. Nevertheless, RS-232 devices are still used, especially in industrial machines, networking equipment, and scientific instruments.

Reference Site :

1. https://en.wikipedia.org/wiki/RS-232

2. http://www.camiresearch.com/Data_Com_Basics/RS232_standard.html

3. http://www.arcelect.com/rs232.htm

 

rs232-interface-using-max232

 

RS232 Interface using MAX232

 

MAX232CPE Datasheet – RS-232 Drivers / Receivers – Maxim

This IC is dual driver/receiver.

Part Number : MAX232CPE

Function : +5V-Powered, Multichannel RS-232 Drivers/Receiver

Package : 16 Pin DIP Type

Manufacturers : Maxim Integrated

Image

max232cpe-rs-232-driver-receiver-maxim

 

Description :

The MAX220 Thru MAX249 family of line drivers/receivers is intended for all EIA/TIA-232E and V.28/V.24 communications interfaces, particularly applications where ±12V is not available.

These parts are especially useful in battery-powered systems, since their low-power shutdown mode reduces power dissipation to less than 5µW. The MAX225, MAX233, MAX235, and MAX245/MAX246/MAX247 use no external components and are recommended for applications where printed circuit board space is critical.

The MAX220-MAX249 are offered in 26 different packages with temperatures from 0 to +70°C up to -55°C to +125°C. See ordering information table at the end of the data sheet for all package and temperature options.
max232 Datasheet Selection Table

Applications/Uses

1. Battery-Powered RS-232 Systems
2. Interface Translation
3. Low-Power Modems
4. Multidrop RS-232 Networks
6. Portable Computing

MAX232CPE Drivers

The typical driver output voltage swing is ±8V when loaded with a nominal 5kΩRS-232 receiver and VCC= +5V. Output swing is guaranteed to meet the EIA/TIA-232E and V.28 specification, which calls for ±5V minimum driver output levels under worst-case conditions. These include a minimum 3kΩload, VCC= +4.5V, and maximum operating temperature. Unloaded driver output voltage ranges from (V+ -1.3V) to (V- +0.5V).

 

Pinout

max232cpe-datasheet-pinout

 

MAX232CPE Receivers

EIA/TIA-232E and V.28 specifications define a voltage level greater than 3V as a logic 0, so all receivers invert. Input thresholds are set at 0.8V and 2.4V, so receivers respond to TTL level inputs as well as EIA/TIA-232E and V.28 levels. The receiver inputs withstand an input overvoltage up to ±25V and provide input terminating resistors with nominal 5kΩ values. The receivers implement Type 1 interpretation of the fault conditions of V.28 and EIA/TIA-232E.

Reference Site : [ Wikipedia MAX232 Info ]

MAX232CPE Datasheet PDF

MAX232 pdf

 

Other data sheets within the file : MAX220 Thru MAX249, MAX222C-D, MAX223C-D

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