Question:
What compand mode shall I set the system to?

Answer:

With analog interface, there is no real compand mode at the interface. You can choose either A-law or Mu-law for the DSPs.

With digital interface, there is pre-determined compand mode from the telco/switch - your system wants to be consistent with that compand mode. Normally E1 comes with A-law and Mu-law comes with T1. However, Pika system DOES allow you to set the interface to be Mu-law for E1 or A-law for T1. You want to make sure all the DSPs are having the same compand mode as the interface.