A European format for digital transmission. E1 supports signals at 2 Mbps (32 channels at 64Kbps, with 2 channels reserved for signaling and controlling), versus the T1, which carries signals at 1.544 Mbps (24 channels at 64Kbps).
Call center - is a center where the company's incoming and outgoing calls are taken care of, it can be a centralized office, used for receiving and forwarding high volumes of information, incoming by the way of phone calls. There are two types of call centers internal call center and outsourced call center.