communicating with Serial devices

Has anyone managed to get an Arduino board talking with another serial device ie. serial LCD?

How do you use the TX and RX pins?

Hi! sorry about my poor English.

RX at P0 , and TX at P1 , I use the “TTL” direct control a serial camera or a BT module , it work well!

RX-- device’s TX
TX-- device’s RX
Gnd-- Gnd

if the device is use Rs232 ,you may need a “3223” to conversion TTL to RS232

sorry about my poor English. I hope you can understand me .