The EEPROM test doesn't work yet, but that may be related to the wrong-ish SFP
connector placed on the board.

Lengthy clarification: the PTS for the CONV-TTL-RS485 boards is inspired from
the PTS of CONV-TTL-BLO, where an SFP+ connector is used. Since the
CONV-TTL-RS485 uses just an SFP connector (not the SFP+), there might be
something wrong when reading the I2C interface. Reading the manuals yielded no
relevant reasons why this would occur, but I'm still investigating.

Either way, the link up test works, just the EEPROM test needs to be clarified
why it doesn't work. And the SFP changed for an SFP+.