3Com VCX V7122, Installation Manual

Page: 7 / 58

Notices 7
Where network appears in this manual, it means LAN, WAN, etc.
accessed via the gateway's Ethernet interface.
FXO ( F oreign E x change O ffice) is the interface replacing the analog
telephone and connects to a Public Switched Telephone Network (PSTN)
line from the Central Office (CO) or to a Private Branch Exchange (PBX).
The FXO is designed to
receive line voltage and ringing current, supplied
from the CO or the PBX (just like an analog telephone). An FXO VoIP
gateway interfaces between the CO/PBX line and the Internet.
FXS ( F oreign E x change S tation) is the interface replacing the Exchange
(that is, the CO or the PBX) and connects to analog telephones, dial-up
modems, and fax machines. The FXS is designed to
supply line voltage
and ringing current to these telephone devices. An FXS VoIP gateway
interfaces between the analog telephone devices and the Internet.
WARNING: Ensure that you connect FXS ports to analog telephone or to
PBX-trunk lines only and FXO ports to Central Office (CO)/PBX lines only.
The V7122 gateway is supplied as a sealed unit and must be installed or
serviced only by qualified service personnel.