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).
The selective call acceptance allows controlling incoming calls by making a list of telephone numbers which you are ready to accept. But incoming calls from subscribers that are not listed are directed to the answering machine by which the caller is informed that you do not accept calls at the moment.