i have gone around the problem by just looking for correct value of the high pause duration as i know if signal is valid and correct should always work

Main:

' PULSIN GPIO.0,1,Leader ' leader pulse is high going on port 0
' IF Leader < 400 tHEN main ' look for 4,5ms high pulse below 400ms then its 2nd key area pulse or data/ address bits
' if leader > 480 then main ' above 480 then its no sig