Could anyone recommend a high speed PCI-bus SSP capable of 10Mbps supplied with suitable drivers to interface to a dotNET application?

• Data is sent via RS422 type drivers with differential twisted screened pairs terminated at both ends.
• Data is accompanied by a clock with +ve transitions mid-bit.
• Every 5 msec the data stream transmits 2000 bytes
• Each byte will have one start bit, eight data bits and one stop bit (no parity).