From The Mega Man Universe
JammingMan is an autonomous Net Navi who served Cache. He was deployed at a mobile communications station and, using the enormous antenna at the station, sent out a jamming signal that blocked Navis from being plugged into machines. Furthermore, Navis who were already plugged in could not talk to their operators nor download Battle Chip data. JammingMan seems to have no personality, and his manner of talking is very computer-like.
Not much is known about JammingMan's battle abilities outside of Japan. He is an electric type Navi, and from screenshots it appears he can make electrical pylons like ElecMan's.