Airlink EDGE/GPRS - Manual (Page 112)

PinPoint-E EDGE/GPRS - User Guide, version 2.32 106
AT Commands: Friends
255 = allow any number 0-255
Example: 166.129.2.255 allows access by all IPs in the range 166.129.2.0-166.129.2.255.
ATF? will return a list of all the current Fn settings.