make sure you tx and rx are connected correctly
controler to gps unit
tx to rx
rx to tx
next… gps may not start sending data immediatly… especially inside with a cold boot
these are the only ideas that could be hardware specific
last some gps use faster or slower speeds maybe try 4800 or 19200
also may check configuration i think neo7m has a windows app that connects thru the usb cable to access the settings in the chip
hope something helps