The Geoport Clock Connector has nothing to do with updating the Geoport to higher clock speeds. This connector is used by Peripheral Component Interconnect (PCI) cards that perform some type of network interaction with the Geoport. It provides the network clock to which the Geoport is talking. Most of the PCI cards that utilize the Geoport Clock Connector are some type of video conferencing cards, such as the H.320 card.
Apple added the Geoport Clock Connector to the logic board because not all PCI cards are physically connected to the network. Without this physical connection the PCI cards would have a difficult time synching with the network clock. If, on the other hand, the network is directly connected to the PCI card, the Geoport Clock Connector is not used at all. By synching to the network clock, the PCI card can determine what kind of timing is needed to execute certain sequences or to provide a refresh to the screen.
There are three pins in the Geoport Clock Connector. One pin is the ground. The other two pins are signal pins. The two signal pins are Serial Clock (SCLK) and Transmit Handshake (TxHs). The GeoPort specification recommends that the GeoPort device provide network synchronized clocking on either SCLK or TxHs. The H.320 card, for example, can then use the appropriate signal to synchronize its video and audio compression/decompression processing to the network.
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