Linksys BUSINESS SPA922 - Manual (Page 15)

Linksys SPA9x2 Phone Administration Guide
Cisco Confidential--First Draft
8
SPA9000 IP PBX System
Introducing Linksys SPA9x2 Phones
SIP Proxy
Switch
SPA9000
UserA
UserB
SPA400
1 to 4 DID lines
SIP-PSTN
Gateway
UserD
PSTN switch
Internet (WAN) Interface