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Cisco Unified SCCP and SIP SRST System Administrator Guide
OL-13143-04
Integrating Voice Mail with Cisco Unified SRST
Revised: December 12, 2011
This chapter describes how to make your existing voice-mail system run on phones connected to a
Cisco Unified SRST router during Cisco Unified Communications Manager fallback.
Cisco Unified SRST also supports incoming and outgoing Session Initiation Protocol (SIP) calls to and
from Cisco Unified IP phones and router voice gateway voice ports. SIP may be used in situations where
the Cisco Unified SRST Router is separate from the PSTN gateway and the SRST and PSTN gateways
are linked together using SIP (instead of H.323).
For more information about SIP, see
Cisco IOS SIP Configuration Guide
.
Contents
•
Information About Integrating Voice Mail with Cisco Unified SCCP SRST, page 235
•
How to Integrate Voice Mail with Cisco Unified SCCP and SIP SRST, page 237
•
Configuration Examples for SCCP SRST, page 249
•
How to Configure DTMF Relay for SIP Applications and Voice Mail, page 252
•
Where to Go Next, page 256
Information About Integrating Voice Mail with
Cisco Unified SCCP SRST
Cisco Unified SCCP SRST can send and receive voice-mail messages from Cisco Unity and other
voice-mail systems during Cisco Unified CM fallback. When the WAN is down, a voice-mail system
with BRI or PRI access to the Cisco Unified SCCP SRST system uses ISDN signaling (see
Figure 1
).
Systems with Foreign Exchange Office (FXO) or Foreign Exchange Station (FXS) access connect to a
PSTN and use in-band dual tone multifrequency (DTMF) signaling (see
Figure 2
).