Since the filename you provided ( Ap3g1-k9w7-tar.153-3.jf15.tar ) refers to a specific Cisco IOS software release for the (specifically those equipped with 802.11g radios, indicated by the g1 ), I have constructed a comprehensive technical review of this firmware image below.
Here is exactly what this file is, where to find it, and how to flash it onto your AP. Ap3g1-k9w7-tar.153-3.jf15.tar Download -
When downloading files with obscure names, especially from untrusted sources: Cisco Aironet 1200 Series Access Points Since the
.153-3 could indicate a version or build number.