TX and RX connected?

I am currently reverse engineering a USB dongle programming device for an ESC (brushlesshobbies.com). It runs on a SILABS MCU. The 3 pin plug is the standard RC Ground, Power, Data. Only the data line is used for a two way communication. Upon inspection of the circuit board the TX/RX pins are connected together with some 1K resistors to the single data line like so: RX -/\/- TX -/\/- Data How does this work and is it possible to emulate with an Arduino?