[cyclohexane]

The D50 does not have a commander flash mode for TTL or AA flash operation with the SB-600.* If the SB-600 has an SU-4 module (like the SB-800) you can rig the flash to fire in response to the pop-up flash, but you cannot control the flash output of the SB-600 from the D50.* There's an SU-4 module you can purchase to add to the bottom of the flash if it doesn't have one built in.

The SC-17 is the old i-TTL sync cord that retains camera/flash communication; I don't know the part number of the new one compatible with i-TTL.* I think it's SC-28 but I don't know.* You should check your instruction manual to see which one is apporpriate.