Cisco 8800 Series Administration Manual page 317

Cisco IP Phone Troubleshooting
Parameter
Referral Services Codes
Description
These codes tell the IP phone what to do when the
user places the current call on hold and is listening to
the second dial tone.
One or more *code can be configured into this
parameter, such as *98, or *97|*98|*123, and so on.
Max total length is 79 chars. This parameter applies
when the user places the current call on hold (by Hook
Flash) and is listening to second dial tone. Each *code
(and the following valid target number according to
current dial plan) entered on the second dial-tone
triggers the phone to perform a blind transfer to a
target number that is prepended by the service *code.
For example, after the user dials *98, the IP phone
plays a special dial tone called the Prompt Tone while
waiting for the user the enter a target number (which
is checked according to dial plan as in normal dialing).
When a complete number is entered, the phone sends
a blind REFER to the holding party with the Refer-To
target equals to *98<target_number>. This feature
allows the phone to hand off a call to an application
server to perform further processing, such as call park.
The *codes should not conflict with any of the other
vertical service codes internally processed by the IP
phone. You can empty the corresponding *code that
you do not want to the phone to process.
Cisco IP Phone 8800 Series Multiplatform Phones Administration Guide
Vertical Service Activation Codes
301