exten => 2,2,NoOp(FORWARD is ${FORWARD})
exten => 2,3,Set(DB(forward/${CALLERID(number)})=${FORWARD})
exten => 2,4,NoOp(forward/${CALLERIDNUM} is ${ DB(forward/${CALLERIDNUM} ) } )

-- Executing NoOp("SIP/148-9227", "FORWARD is 137") in new stack
-- Executing Set("SIP/148-9227", "DB(forward/148)=137") in new stack
-- Executing NoOp("SIP/148-9227", "forward/148 is 0 ") in new stack