It is not must to have E1 and T1’s for setting up a call centre.
It depends upon the interface u r getting from the service provider. is it an etheernet interface.
U can distribute this Ethernate interface to 30 channels if u r using E1 and if ur Using T1 it will be 24 channels
so, which means 30 calls can proceed at a time.
i other words to say single input multiple output.
Plz correct me if i am wrong