The label attached to the bottom of the FB2500 shows what MAC address range that unit uses, using a compact notation, as highlighted in Figure C.1 :-

Figure C.1. Product label showing MAC address range

In this example, the range is specified as :-

000397:147C-F

this is interpreted as :-

Therefore this range spans 00:03:97:14:7C:00 to 00:03:97:14:7F:FF inclusive (1024 addresses). If you are trying to identify an IP address allocation, note that the exact address used within this range depends on a number of factors ; generally you should look for an IP address allocation against any of the addresses in the range.

Alternatively, if the range specification doesn't include a hyphen, it specifies that all addresses in the range start with this 'prefix' - the first address in the range will have zero for all the remaining digits, and the last address in the range will have F for all the remaining digits. For example :-

000397:147C

is interpreted as :

Therefore this range spans 00:03:97:14:7C:00 to 00:03:97:14:7C:FF inclusive (256 addresses).