About Dtmf Settings; About Dtmf - Cisco 3521 Administrator's Manual

Chapter 3 Configuring the Cisco IPVC 3500 Series Gateway
Table 3-8
Field or Check Box
Restrict Gateway use to MCU conferences only Select for the gateway to send and receive calls to
Support Presentation Restriction
Support H.239

About DTMF Settings

The Cisco IPVC 3500 Series Gateway performs Dual Tone Multi-Frequency (DTMF) detection on
IP-to-ISDN calls and on ISDN-to-IP calls. The gateway can send DTMF tone information to the IP
endpoint. in-band only or both in-band and out-of-band. The gateway sends DTMF tone information to
the ISDN endpoint in-band only.
Note For PRI Gateways, enabling DTMF detection for video calls reduces the number of supported calls at
128 Kbps from 30 to 22.

About DTMF

The signal generated by a DTMF encoder is a direct algebraic summation, in real time, of the amplitudes
of time sine (or cosine) waves of different frequencies.
An example of the use of DTMF is in touch tone telephone dialing. DTMF tones are sent out as you dial.
For example, pressing "1" sends a tone created by combining frequencies of 1209 Hz and 697 Hz.
Administrator's Guide for Cisco IPVC 3521 BRI Gateway, Cisco IPVC 3526 PRI Gateway, and Cisco IPVC 3540 PRI Gateway
OL-7995-01
Advanced Settings
Configuring Gateway Settings
Description
and from a Cisco IPVC 35xx MCU only. This
setting, together with a scheduling server,
reserves resources for scheduled conferences
only.
Select to enable support for the presentation
restriction feature. This feature responds to an
instruction from the calling endpoint to forward or
to conceal the endpoint identifier.
Select to enable support for dual video channels
using the H.239 protocol. This setting is selected
by default.
When selected, the gateway supports H.239 in
ISDN-to-IP calls and in IP-to-ISDN calls. the
gateway identifies the protocol version that an IP
endpoint uses and sends H.239 capabilities only
to those endpoints working with protocol version
4.0 or later. H.239 support has no impact on
gateway capacity.
We recommend that you do not enable this feature
if you establish communication with endpoints
that do not support H.245 generic capabilities
(endpoints based on H.323 version 2 or earlier) as
this might cause the endpoints to fail upon
receiving these capability exchanges.
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