User manual

Chapter 1
Overview
The 800 Series cards are versatile devices used for connecting your phone
network to the PSTN (Public Switched Telephone Network) world. This
is accomplished through phone lines connected to the FXO (Foreign
Exchange Office) ports and phones connected via the FXS (Foreign
Exchange Station) ports. The cards allow Asterisk to connect to your
phone network, creating an office type telephony environment.
There are a variety of applications where the 800 Series cards (TDM800P
or AEX800) can prove useful. An example is provided in the following
figure.
Figure 1: Sample Card Application
Note: An FXS module should be connected only to a device that is
located inside of the same building to minimize lightning exposure.
Digium, Inc. Page 13