Have spent several interesting but largely fruitless hours trying to make some progress with the program.

However if I jump passed the COUNTER / WDT routine the TX & RX work fine which is good to know.

Here's the code for it:

Code:
      COUNTER=0        ' clear before entry
WHILE COUNTER <= 2     ' 4.608sec Loop time (Loop for 30 mins = 781)
     INTCON.0 = 0      ' Clear int on change flag
     @ SLEEP
     @ NOP 
     CLEARWDT
     COUNTER=COUNTER+1
One thought does occur to me though, at the start of the program the PIC is placed into SLEEP mode, only to be woken on INTERRUPT.

Code below.

Code:
IF GPIO.3= 1 AND GPIO.4= 1 THEN ' Nothing has happened so SLEEP
       E_OUT=0       ' Disable transmitter
       INTCON.0 = 0  ' No Inputs detected or it's still light so clear int on change flag
       @ SLEEP       ' and start snoozin..zzzzzzzzzzz indefinatly
       @ NOP         ' Do nothing for 1st instruction on wake-up
       CLEARWDT
  ELSE  
   'IF  GPIO.3=0 THEN GOSUB COUNTS 'Bird detected at box - GOTO LABEL COUNTS   
   IF  GPIO.4=0 THEN   encode 'DARK 'Encode 'DARK   'It's got dark? or just cloudy - GOTO LABEL DARK
However, GPIO.4 must be pressed and held down (simulating night time) which causes the wake up from SLEEP interrupt, the program then moves down to the COUNTER / WDT loop. I think I might have found a problem here though. For the COUNTER / WDT loop to work and give a 4.6sec test delay the PIC must go into SLEEP mode, if GPIO.4 is continually held down simulating night time and hence causing an INTERRUPT from SLEEP (continually, even resetting the interrupt won't help as button continually pressed) then my thinking says the COUNTER /WDT loop will never work because the PIC is always being woken up.

A bit garbled I know, sorry, but am I onto something.

Dave