MAX232 is the most famous integrated conceived for this aim, firstly introduced by Maxim but was (and it still is) produced by several semiconductor firms, it is an integrated circuit that allows communication between TTL or CMOS logic at 5V and EIA RS-232 voltage just with 5V power supply.
To obtain the postive and negative voltage needed for the operation it’s used a charge pump configuration, made up of some circuits located in the integrated itself and 4 external capacitors.
In that ready to use electronic board you find RS232 - TTL MAX3232 serial converter (improved version of 232) that requires a power supply of 3.3Vcc and 4 capacitors of only 100nF to work.
The inverting gates of the integrated circuit are able to absorb a voltage in the range of ±12Vcc and give as output a TTL compatible signal, whereas the broadcasting section is composed of 2 inverting drivers that receive a TTL compatible signal and can dispense a vacuum voltage about ±10Vcc , compatible with EIA RS-232 standard.
The adapter is given completely assembled in all it’s smd components, including the 9-pin serial connector.
The 2.54mm standard pitch connector and the technology of the integrated circuit make this module perfectly compatible with breadboard, microcontrollers and demoboards.
Working voltage : 3 ~ 5,5V
Serial Standard: TIA/EIA-232-F
Female DB9 connector
Connection strip: 2.54mm
Dimensions: 31 x 35 x 11 mm (connettore e pin inclusi)
Working temperature range: 0° ~ 70°
Weight: 11 g
To get more informations about technical specifications have a look at : Convertitore seriale RS232 - TTL.pdf MAX3232 e Additional Information