You can stream 16 channels between the Konnekt 24D and the computer via FireWire. They are as follows:
4 simultaneous analog inputs. It has 2 (channel 1 + 2) on the front and 4 (channel 1, 2, 3 + 4) on the back.
4 of these can be used simultaneously.
8 simultaneous digital inputs. It has 2 S/PDIF and 8 ADAT connections.
8 of these can be used simultaneously either as:
4 effects channels. Stereo return from the Fabrik R + the 2 mono outputs of the 2 Fabrik Cs. This essentially allows you to set up the Fabrik C and Fabrik R as an external device you can set up in a send/return configuration from within your host program.
Out of these 16 channels, you can use 12 physical inputs + physical 12 outputs (hence the '24' in the product name) simultaneously.
For more detailed information on the inputs and outputs, please see the Konnekt 24D / Konnekt Live productpages.