Specifications

Appendix C VoIP Configuration Examples
C-10
Catalyst 4224 Access Gateway Switch Software Configuration Guide
OL-2031-02
FXO Gateway to PSTN
Foreign Exchange Office (FXO) interfaces provide a gateway from the VoIP
network to the analog public switched telephone network (PSTN) or to a PBX that
does not support Ear and Mouth (E&M) signaling.
In this scenario, users connected to Catalyst 4224 SJ in San Jose, California, can
reach PSTN users in Salt Lake City, Utah, via Catalyst 4224 SLC. Router SLC in
Salt Lake City is connected directly to the PSTN through an FXO interface.
Figure C-3 illustrates the topology of this scenario.
Figure C-3 FXO Gateway to PSTN (Example)
Note This example assumes that the company has already established a working IP
connection between its two remote offices.
58513
[phone]
(801) . . . . . . .
Catalyst 4224 SJ
San Jose
Salt Lake City
Catalyst 4224 SLC
172.16.1.123
172.16.65.182
PSTN user
Voice port
0/0
IP cloud
Voice port
0/0
PSTN
cloud
V V