If you have to make a PRI E1/T1 card driver compatible with asterisk...
1. The driver should define span structure
2. The driver should define functions such as ioctl, spanconfig, open, close, rbsbits etc
3. The span variables should be populated with corresponding functions and values
4. In the device init, call zt_register with the populated span.
Next: What are the functions of methods populated in span?