Specifications

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Cisco Unified Survivable Remote Site Telephony Version 4.0 System Administrator Guide
Overview of Cisco Unified SRST
This chapter describes Cisco Unified Survivable Remote Site Telephony (Cisco Unified SRST) and what
it does. It also includes information about Cisco Unified IP Phone, platform, and Cisco Unified
CallManager version support; specifications; features; restrictions; and where to find additional
reference documents.
Note Prior to version 4.0, the name of this product was Cisco SRST.
Note For the most up-to-date information about Cisco Unified IP Phone support, the maximum number of
Cisco Unified IP Phones, maximum DNs or virtual voice ports, and memory requirements for
Cisco Unified SRST, see the Cisco Unified SRST 4.0 Supported Firmware, Platforms, Memory, and
Voice Products
at
http://www.cisco.com/en/US/customer/products/sw/voicesw/ps2169/prod_installation_guide09186a00
805f6f1b.html.
Contents
• Cisco Unified SRST Description, page 23
• Support for Cisco Unified IP Phones, Platforms, Cisco Unified CallManager, Signals, Languages,
and Switches, page 27
• Prerequisites for Configuring Cisco Unified SRST, page 31
• Restrictions for Configuring Cisco Unified SRST, page 33
• Where to Go Next, page 35
• Additional References, page 35
Cisco Unified SRST Description
Cisco Unified SRST provides Cisco Unified CallManager with fallback support for Cisco IP phones that
are attached to a Cisco router on your local network. Cisco Unified SRST enables routers to provide
call-handling support for Cisco IP phones when they lose connection to remote primary, secondary, or
tertiary Cisco Unified CallManager installations or when the WAN connection is down.