100BASE-TX (MLT-3) to 100BASE-FX (NRZ-I) conversion
I haven't seen a bridge that runs a 100Base-TX phy directly into a 100Base-FX phy, all the devices I've seen have some kind of processor between the two which makes sense because the 100Base-FX uses a star network and would be difficult to simply copy all packets from one physical media to the other.