RS232 in the year 2014 ??? Yes ! As it is still the mother of all serial communications - and we use it often, we put this information here.
As memory or clock stability is nowadays a self-evidence, we dropped that handshaking stuff. Only RX and TX are used. And they are used therefore,
as the microprocessor would call them. The used 6-pin header has always the same pin assignment, so they (RS232,USB,XPORT,...) are all interchangeable.
The device may easily be tested using HTerm in a loopback configuration.
(RX is tied to TX and so the data is send back to the computer). Current consumption was 6 mA at 5 V.
On the left side we see the RX signal which has almost 5 Vpp. On the right side : TX. We also see, that a logic one (high) is translated to
-10V, whereas the logic zero (low) is +10V. The settings were 9600,8,N,1. The LSB is transmitted first. In binary
form the word 'HOLA' looks like this :