Oops - you've got me seeing double -

.
Okay - I've had a look at the BCM and need to clarify my question a little more:
1. I now know that we are paying the telco for 30 physical lines which are coming into the building via 2 pairs; I believe the pairs are segregated to incoming and outgoing - is it balanced as 15 lines each direction or is the system intelligent enough to allow 20/10 or 12/18 as the case may be?
2. How the lines are extracted from these 2 pairs (most likely one pair is for incoming and the other for outgoing calls) is one thing I'd like to know.
3. I have also seen that there are numerous target lines (we are using from 241 to 340 to cater for 100 extensions in the building). How would I go about, for instance, linking a target line to an extension?
This sounds like it is different from the question originally asked as I now realize that my initial question was not well thought out!
Cheers,
tk.