[Asterisk-Users] type of incoming lines

[mike webb]

at my work we have a meridian 1. it has 6 lines from the outside world 
coming in to it. if someone calls our number 870-238-2111 they will 
always reach our resepsionist unless all 6 lines are in use, if all 6 
are in use then the caller will get a busy signal.
on our phone bill they are called "trunk lines".
we have a seperate incoming line for our dsl.

are these analog lines ?? to connect to an asterisk system would i use 
fxo's ??
what term do you use to describe them, partial t1, pri,etc ??