IP to SU:
SU 10 to 249, IP address = 192.168.209.SU#
ex. SU 188 has ip 192.168.209.188

SU 250 to 489, IP address = 192.168.109.(SU#-240)
ex. SU 310 has ip 192.168.109.70

SU 510-778, IP address= 192.168.9.(SU#-500)
ex. SU 533 has ip 192.168.9.33