CAS-EL7:

The E1 CAS EL7 interface is a digital 2.048Mb 32-channel interface that can provide up to 30 CAS (Channel Associated Signaling) voice mail ports per E1 link. DTMF signaling and voice communications are performed over the established E1 link.

The MD110 Voice Mail interface is an Ethernet network connection that uses the TCP/IP protocol to communicate. Calling and called party information is sent via TCP/IP over the network connection at the same time that a call is sent to a CAS channel. The data is matched with the ringing channel and answers with the appropriate dialog. Message Waiting Indicator (MWI) operation is also performed via TCP/IP over the network connection.