Does the MTA128ST have an internal 100 Ohm terminating resistor?
The Rev. J and newer board revisions has jumpers that provide 100 ohms. The two jumpers are near the RJ-45 jack on the board. The shunt is provided on the board for the two 100 ohm termination resistors and by default the shunt is in the disconnected position of the 3-pin berg jumper.The Ref. F and older revision boards don't have the termination resistors, but they can be added with some soldering skills.