Thanks,
at the moment my hardware consist of pic 18f1320, a tsal6100 emitter and tsop4038 receiver.
The emitter is driven by a bs170 mosfet and it handles about 200 mA of current.
I did transmit some burst of 38khz carrier and I got the required distance that is around 20 meters: that is OK for me now.
The small piece of code is like this:
LOOP:
HPWM 1, 127, 38000
PAUSE 1
HPWM 1, 0, 38000
PAUSE 100
GOTO LOOP

Now how could I modulate the carrier using the serial ( UART data ) ?
Thanks
Ambrogio