Specifications

Setting Up Call Handling
How to Set Up Call Handling for Incoming and Outgoing Calls
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Cisco Unified Survivable Remote Site Telephony Version 4.0 System Administrator Guide
Enabling Analog Transfer Using Hookflash and the H.450.2 Standard with Cisco SRST 3.0 or Earlier
Analog call transfer using hookflash and the H.450.2 standard allows analog phones to transfer calls with
consultation by using the hookflash to initiate the transfer. Hookflash refers to the short on-hook period
usually generated by a telephone-like device during a call to indicate that the telephone is attempting to
perform a dial-tone recall from a PBX. Hookflash is often used to perform call transfer. For example, a
hookflash occurs when a caller quickly taps once on the button in the cradle of an analog phone’s
handset.
This feature requires installation of a Tool Command Language (Tcl) script. The script
app-h450-transfer.tcl must be downloaded from the Cisco Software Center at
http://www.cisco.com/cgi-bin/tablebuild.pl/ip-iostsp and copied to a TFTP server that is available to the
Cisco Unified SRST router or copied to the flash memory on the Cisco Unified SRST router. To apply
this script globally to all dial peers, use the call application global command in global configuration
mode. The Tcl script has parameters to which you can pass values using attribute-value (AV) pairs in the
call application voice command. The parameter that applies to this feature is as follows:
• delay-time—Speeds up or delays the setting up of the consultation call during a call transfer from
an analog phone using a delay timer. When all digits have been collected, the delay timer is started.
The call setup to the receiving party does not begin until the delay timer expires. If the transferring
party goes on-hook before the delay timer expires, the transfer is considered a blind transfer rather
than a consultative transfer. If the transferring party goes on-hook after the delay timer expires,
either while the destination phone is ringing or after the destination party answers, the transfer is
considered a consultative transfer.
In addition to the Tcl script, a ReadMe file describes the script and the configurable AV pairs. Read this
file whenever you download a new version of the script because it may contain additional script-specific
information, such as configuration parameters and user interface descriptions.
Note For Cisco SRST 3.1 and later and Cisco Unified SRST 4.0 and later, call transfer using H.450.2 is
supported automatically with the default session application.
Prerequisites
• The H.450 Tcl script named app-h450-transfer.tcl must be downloaded from the Cisco Software
Center. The following versions of the script are available:
– app-h450-transfer.2.0.0.2.tcl for Cisco IOS Release 12.2(11)YT1 and later releases
– app-h450-transfer.2.0.0.1.tcl for Cisco IOS Release 12.2(11)YT
• All voice gateway routers in the VoIP network must support H.450 and be running the following
software:
– Cisco IOS 12.2(11)YT or a later release
– Cisco SRST V3.0 or a lower version
– Tcl IVR 2.0
– H.450 Tcl script (app-h450-transfer.tcl)
Note You can continue to use the app-h450-transfer.2.0.0.1.tcl script if you install Cisco IOS
Release 12.2(11)YT1 or later, but you cannot use the app-h450-transfer.2.0.0.2.tcl script with a release
of Cisco IOS software that is earlier than Cisco IOS Release 12.2(11)YT1.