3com V7111 User Manual

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Abbreviations and Terminology 
Each abbreviation, unless widely used, is spelled out in full when first used. Only industry-
standard terms are used throughout this manual. Hexadecimal notation is indicated by 0x 
preceding the number. 
Where "network" appears in this manual, it means LAN, WAN, etc. accessed via 
the gateway's Ethernet interface. 
 
FXO (F
x
O
oreign E change  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
x
S
oreign E change  tation) is the interface replacing the Exchange (i.e., 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 V7111 is supplied as a sealed unit and must only be installed or serviced by 
qualified service personnel. 
 
10 
3Com VCX V7111 Analog Gateway Installation Guide