I have a fiber optic cable that I cannot get to "turn up" on my HP 4108GL switchs. The modules I have in the switches are the HP ProCurve Gigabit-SX Tranceiver (J4131B) on both switches. The fiber optic I'm trying to use is a Corning 62.5/125 MM TB2 OFNR. I know the modules work with another fiber. I have switched the fibers to see if they were backwards, but no go. Any suggestions? The fibers are going directly into the switches. I have four fibers and none of them work. I do not have access to a fiber tester, so that is out. The fiber is new, so Im assuming the SC ends are OK.