Number of Channels

Hello,

I'm relatively new to the Dialogic cards and have few questions:

1. How do I find out the number of channels on a detected board ? iterate with dx_open ?

2. Can anyone recommend a good review explaining the different technologies and the boards associated with them  ?

3. What is the relationship between the different API libraries (SRL, Voice, GC, BRD) ? are they complementary to each other or are they dedicated to specific boards / firmware ?

Thanks.