I have a DS18B20 Temperature Sensor connected to the display via a PICAXE 20M2 running this code from the manual
temp:
pause 500
serout B.3,N2400, (0)
pause 400
readtemp B.4,b11 ; read value into b1
if b11 > 127 then negative ; test for negative
serout B.3,N2400,(254,142,#b11)
pause...