It is a device capturing and controling all the signals, which are being created by the whole system, especially the made and received phone call signals. The device is mostly used for connecting regular phone system with the Internet and backwards.
TDM800P is an eight Port analog PCI 3.3/5.0V Card equipped with echo cancellation and 8 Trunk Interfaces. This is a half length PCI 2.2 complaint, 8 port card meant for connection of analog POTS lines and analog phones via personal computer. It provides support for combinations of FXO and FXS modules maximum of eight lines.