Can be because you don't have do some definessssss

Code:
This is:
'SERout MASTER
include "modedefs.bas"
TRISB.0=0
B0 var byte

B0 = %00000001 

loop: 
     Serout PORTB.0,T2400,[B0]
     Pause 100
     goto loop 


----------------------------------------

' SERin slave
include "modedefs.bas"

TRISB.1=1
A0 var PORTB.1

TRISB.0=0
B0 var PORTB.0

DataRec Var byte

loop: 
     Serin A0,T2400,DataRec 
     Serout B0,T2400,DataRec  

     goto loop
i don't like to say that but, look into your PBP book in the SERIN/SEROUT section... and do a search within this forum, and on the Melabs website in the code example section.