RS-232 for approx 1600ft
Can someone please suggest on what should be the correct approach to enable communication using RS-232 for such long distance.


No, because RS-232 was never designed to work over such distances. A long cable like that picks up a lot of noise and interference, like an antenna. Because RS-232 is single-ended, this noise and interference is impossible to distinguish from a real signal. Every(?) protocol designed for longer distances or faster speed will use differential signaling, which, roughly speaking, sends a mirrored copy of the data at the same time as the normal version. That way, the interference can be canceled out.

The closely related RS-422 and RS-485 will work far better, and it is easy to convert from RS-232 to RS-422/485 and then back to RS-232 on the other end. These standards were designed to run over the lengths of cable you want, but has the small drawback of requiring twice as many wires for the data. RS-485 can work in half-duplex mode, using the RS-232 RX/TX as one pair, if you don't have enough signal lines.

Numerous converters exist on eBay for 2 USD with free shipping, or, depending on your application, there are TTL&lt;->RS-422/485 converters for microcontrollers.