Not sure if this will work but it compiles with PBP.
square brackets in the serout command are used in place of ()
This is the TX code. Should be able to do the same with the RX..
Code:
   INCLUDE "modedefs.bas"
    B0  var BYTE
    B1 VAR BYTE

trisb = 134
trisa = 133
portb = 6
porta = 5
low 1
input 0
input 2

start:
pot 0,50,B0

pot 2,50,B1
B0 = B0 * 5
B1 = B1 * 5
y:
if B0 < 100 then yf
if B0 > 150 then yb
  
x:
if B1 < 100 then xr
if B1 > 150 then xl
serout 1,n9600,[5]
goto start

yf:
serout 1,n9600,[2]
goto start

yb:
serout 1,n9600,[1]
goto start

xl:
serout 1,n9600,[3]
goto start

xr:
serout 1,n9600,[4]
goto start

end