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
E1’s has 32 voice channels > mostly used Europe and some parts of Asia.
T1’s 24 voice channels standard in North America.
you should verify with your Circuit provider ( Telephone Company ) what standard they are using whether it’s T1 or E1 and from there they can make recommendations as to what equipment/card/cable you need to for your equipment.