Voice Over IP

TERMINATING THE MODEM ANALOG SIGNAL

As a general rule, voice and data service providers attempt to terminate the modem analog signal and convert it to a digital signal as soon as practicable. Figure 5-4 shows three scenarios in how the analog modem termination can be handled.^[2] The goal is provide this termination as close to the subscriber as possible, which allows more efficient techniques to be used on the remainder of the link to the Internet or corporate node. The shadowed boxes in the figure that are numbered 1, 2, or 3 symbolize the demarcation point at which the modem signals (modem connection) are terminated. Thereafter, digital signaling is employed at the physical layer, with Frame Relay or ATM operating over the physical layer, and ...