Robonova serial comm prob

[skycruiser]

I'm a beginner as far as Robonova 1 is concerned.So do help me if you can.I can very well program the C3024 controller on my robonova thru my laptop(programming process is seen clearly on oscilloscope).I'm using a USB to serial converter cable.
But when I write a program to send a byte on serial cable by command ETX and then trying to recieve a byte from my laptop(by command ERX), I don't see any activity(even on the oscilloscope) and the program reaches the end(Depicted by Music command).Please guide me.It would help if someone could give a program which transmits and receives a byte on serial cable for 3024 controller.My program is pasted below:

PTP SETON
PTP ALLON

'TEMPO 230
'MUSIC "C"
DIM I AS BYTE
DIM A AS BYTE

'== motor diretion setting ======================
DIR G6A,1,0,0,1,0,0
DIR G6B,1,1,1,1,1,1
DIR G6C,0,0,0,0,0,0
DIR G6D,0,1,1,0,1,0

'== motor start position read ===================
GETMOTORSET G6A,1,1,1,1,1,0
GETMOTORSET G6B,1,1,1,0,0,0
GETMOTORSET G6C,1,1,1,0,0,0
GETMOTORSET G6D,1,1,1,1,1,0

SPEED 5
'MUSIC "E"

'== motor power on =============================
MOTOR G24

GOSUB standard_pose
DELAY 1000


'================================================
MAIN:
I = "1"
ETX 9600, I
A = "1"
MUSIC "CC"
Retry:
ERX 9600, A, Retry
GOTO MAIN
'================================================
standard_pose:

MOVE G6A,100, 76, 145, 93, 100, 100
MOVE G6D,100, 76, 145, 93, 100, 100
MOVE G6B,100, 30, 80, 100, 100, 100
MOVE G6C,100, 30, 80, 100, 100, 100
WAIT

RETURN
'================================================