Audison F2O Optical Extension Card SPDIF Input for Forza AF M & C bit AmplifiersF2O FORZA OPTICAL EXTENSION BOARD Accessories Forza extension board The F2O accessory is a digital input extension card, compatible with the new line of Audison AF bit amplifiers with integrated Dsp. The card fits the dedicated external slot of the AF bit amplifier and it adds an additional Coaxial S PDIF or a second Toslink S PDIF input. The type of additional input can be selected by the switch mounted over the card itself.