dynamixel servo using arduino

HI

i am using ax12a library to control dynamixel using arduino

issue 1

when i dont use any buffer ic like 74ls241 and directly connect data pin of dynamiel to tx of arduino only turn funtion works,move funtion doesnt work at all

issue 2

when i use any buffer ic like 74ls241 neither turn,nor led blink or move is not working

anything to be changed in library for the functions to work???

Reply with your solutions ASAP