Thank you for reply.
I'm huppy: my question is not so stupid!
I *must* use only PortB.0 pin and reply to PIC-1 like an iButton.
I write this routine for PIC-2 (work fine without ONE error with OSC_INT at 4 MHz):
------------------------
LOOP:
input PortB.0

'wait reset pulse
WAIT_L:
if PortB.0 = 1 then WAIT_L
WAIT_H:
if PortB.0 = 0 then WAIT_H

'tPDH
pauseus 15

'start PRESENCE pulse
low PortB.0
pauseus 60
high PortB.0

'tRSTH
pauseus 450

' read Function Command ($33)
owin PortB.0, 0, [FC]

goto LOOP
---------------------------

But I don't know to continue... :-(
I can send to PIC-1 only a correct byte with OWOUT command, no more.
I think the problem is the timing...

Thanks

cip