I've taken a look inside the two SFP's. http://support.fccps.cz/download/adv/frr/ptp/inside_sfps.zip
The uglier, bigger and likely older model (my SFP#2) contains two PCB's sandwiched, and the key chips are inside the sandwich. Thus, the photoes don't show much. The sexier SFP#1 = the one with the Broadcom chip... I believe it's what it says on the tin: - the BCM5461SA is directly interfaced to a laser driver chip (pretty much analog, found a datasheet from Maxim) - the RX direction seems equally simple, I haven't identified the chip by the marking, but by pinout it's undoubtedly an RX amplifier (they're called transimpedance amps, are they?) and, looking at the PCB traces, its output is directly interfaced to the BCM5461SA. - there's another BGA chip on the board, smaller than the BCM PHY. I believe that this is an "SFP MCU". Might be from Maxim or from someone completely different :-) Not sure whose trademark the "+" sign is in the chip marking. I've found a *slightly* more promising "data brief" from Broadcom for the BCM5461S: http://infiber.ru/assets/files/products/phy/BCM5461S_Product_Brief.pdf This one mentions 100Base-FX among the interface formats supported. I don't believe that the SFP maker would pipe copper MLT3 into the fiber driver+receiver :-) Note that the block diagram in the Broadcom PDF contains other minor errors. God knows what the true functionality is. The SFP#1 PCB still doesn't look fake to me. Frank
