9 Returns a tuple with the first and the last channel in a MM zebra connector.
12 zebra (int) identifies the zebra connector number within a layer. Counting from 0 to 31
15 tuple containing the first and the last strip of a given zebra connector
22 if(zebra>19): zebra -= 20
23 firstChannel = zebra*256 + 1
24 lastChannel = (zebra+1)*256
25 return (firstChannel, lastChannel)