Is it mandatory to use YFGW610 to connect YFGW510 with optical Ethernet (100BASE-FX)? Is it possible to use other model of metal-optical Ether converter?

Communication between the YFGW410 gateway and the YFGW510  access point has strict limitations for delays in order to implement precise time synchronization.  For this reason, the YFGW610 media converter is required when using the YFGW510 with fiber optic communication option.  Using a non-Yokogawa media converter will not allow performance to be guaranteed.