I've been working with an older Catalyst 1900 switch (firmware ver 5.35) We can't get any management console output. We are able to bring up the diagnostic console by holding in the mode button on the front of the switch while turning on the power. After upgrading the firmware via xmodem, the switch will POST and then leave us with a blsnk screen except for modem strings ATQ0H0 and ATQ0Z0. Anyone ever experienced the same issue? I searched all through Cisco's site and didn't find any input.