Wheelchair User Manual

Signaling System 7 (SS7)
System requirements for SS7 operations
APX 8000/MAX TNT/DSLTNT Physical Interface Configuration Guide Preliminary May 9, 2000 18-3
TAOS unit as terminator of voice and data calls in an SS7 network
With the IPDC license, the TAOS unit can communicate with the signaling gateway by means
of IPDC. IPDC enables the TAOS unit to terminate voice or data calls. An example of TAOS
units being used both for Internet call diversion (data) and Voice over IP (VoIP) is shown in
Figure 18-2.
Figure 18-2. TAOS unit terminating voice and data calls in an SS7 network
Connection to the SS7 network is achieved through a signaling gateway. This gateway
provides a bridge to the SS7 network and performs service switching point functions such as
initiating and managing call setup and release, and executing call routing. IPDC must be
supported by both the signaling gateway and the TAOS unit.
The signaling gateway uses the IPDC protocol to convert the SS7 signaling information and
call data from the PSTN into IPDC packets, which are sent to the TAOS unit. In addition, the
gateway uses IPDC to convert IPDC packets received from a TAOS unit into SS7 format
before sending the call to the PSTN.
Before sending call data across the IP network, the TAOS unit uses IPDC to extract TDM and
IP routing instructions from the IPDC packets received from the signaling gateway. The
far-end TAOS unit then forwards IPDC packets to a signaling gateway, which converts them
back into SS7 messages before the call is connected.
SS7
MultiVoice
gateway 2
PSTN
PSTN
Ingress CO
switch
Egress CO
switch
SS7 Network
IMT data
trunk
ISP A
ISP B
ISP C
A-links
Tandem CO
switch
Data and voice path without IPDC
Data path with IPDC
PRI
TCP/IP
Frame Relay,
ATM, or IP
MultiVoice
gateway 1
Signaling gateway
Signaling
gateway
IPDC
IMT
trunk
Voice path with IPDC
TAOS
TAOS