Replacing IR TX/RX by wired connection (for the electronics engineers)

Hi guys,

I have a question for the hands-on electronics engineers roaming this forum:

is it possible to replace an IR TX/RX (single TX to single RX) by a wired one?
my idea is to use an esp8266 to replace the IR and place it inside the controlled unit, and by doing it, be able to control it from any wifi enabled device...
when I got my electronics degree, centuries ago, IR TX modulation was done by the IR TX device, usually a specialized transistor, but being this a recent commercial equipment, I wonder if things have changed...

(I know I can always convert the esp to an wifi to IR bridge and place it incide the unit directly facing the receiver... but anyway...)

Any schematic?
Circuit diagram will help a lot. Without it hard to tell as far as I am concerned.

I managed to hack an old remote which has as tx circuit a classic Transistor drived Led, so the equivalent to any adafruit 3 pin ir sender.

My main problem now is to read the original remote codes, for that I guess I will have to buy an IR rx break-out