User manual

Chapter 4: FXS and FXO Explained
Using Your 800 Series Card
Connect an outside line to an FXO port on your Asterisk server to receive
voltage from the outside line.
Connect phones to FXS ports on your Asterisk server. The recommended
maximum distance from an FXS module to its connected device is 1,500
ft. (457m). When the FXO module in your Asterisk Server receives the
voltage, it will then generate voltage using the FXS module and send it to
your analog phone.
Note: An analog phone line originating from an FXS module must
remain inside the same building as the FXS module. In addition, an
analog phone line originating from an FXS module must not be
bundled with a line or lines that go outside the building where the FXS
module is located.
Caution.
FXS modules are not equipped with lightning protection and
should not be exposed to high voltage. Lightning or high
voltage can cause damage to an FXS module. Damage caused
by lightning or high voltage will void the product warranty.
Digium, Inc. Page 50