Cisco SPA112 Administration Manual page 39

Configuring Voice
Getting Started with Voice Services
Cisco SPA100 Series Phone Adapters Administration Guide
• Echo Cancellation
Impedance mismatch between the telephone and the IP Telephony
gateway phone port can lead to near-end echo. The ATA has a near-end
echo canceller that compensates for impedance mismatch. The ATA also
implements an echo suppressor with Comfort Noise Generator (CNG) so
that any residual echo is not noticeable. These features are enabled by
default. For more information, see the Audio Configuration section in
and Line 2 Settings (PHONE1 and PHONE2), page
• Hook Flash Events
The ATA can signal hook flash events to the proxy during a connected call.
This feature can be used to provide advanced mid-call services with third-
party-call control. You may need to adjust the settings described below.
- Depending on the features that the service provider offers using third-
party-call-control, you may need to disable Call Waiting Service, Three
Way Conference Service, or Three Way Call Service to correctly signal a
hook flash event to the softswitch. For more information, see the
Supplementary Service Subscription section in
Settings (PHONE1 and PHONE2), page
- You can configure the length of time allowed for detection of a hook flash
by using the Hook Flash Timer parameter on the Regional page,
Control Timer Values section. See
page 73.
• Configurable Dial Plan with Interdigit Timers
The ATA has three configurable interdigit timers: an initial timeout signaling
that a phone is taken off hook, a long timeout signaling the end of a dialed
string, and a short timeout, signaling that more digits are expected. For more
information, see Configuring Dial Plans, page
• Polarity Control
The ATA allows the polarity to be set when a call is connected and when a
call is disconnected. This feature is required to support some pay phone
system and answering machines. For more information, see the FXS Port
Polarity Configuration section in
PHONE2), page 90.
• Calling Party Control
Calling Party Control (CPC) signals to the called party equipment that the
calling party has hung up during a connected call by momentarily removing
the voltage between the tip and the ring. This feature is useful for auto
answer equipment. For more information, see the Control Timer Values
section in Voice System Regional Settings, page
90.
Line 1 and Line 2
90.
Voice System Regional Settings,
42.
Line 1 and Line 2 Settings (PHONE1 and
73.
4
Line 1
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