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Configuring general ISDN settings
Cisco TelePresence ISDN Gateways v2.0 Online help (Printable format)
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ISDN advanced settings
Field
Field description
Usage tips
E1 CRC-4 enabled
With an ISDN interface type of E1
selected in the Basic settings, this
option selects whether ISDN
signalling should make use of the
CRC-4 mechanism.
Most E1 ISDN networks require CRC-
4 to be enabled, although some (in
particular, some French networks)
require it to be disabled. Refer to your
ISDN network provider if you are
unsure whether to enable or disable
CRC-4.
The ISDN gateway may have to be
restarted for changes of this setting to
take effect (see
Shutting down the
ISDN gateway
).
T1 ESF enabled
With an ISDN interface type of T1
selected, this option selects whether
ISDN signalling should make use of
the Extended Superframe Framing
technique.
Most T1 ISDN networks require ESF
to be enabled. Refer to your ISDN
network provider if you are unsure
whether to enable or disable ESF.
The ISDN gateway may have to be
restarted for changes to this setting to
take effect.
Send channel ID
in Q.931
Line length
Line impedance
Line coding
Transmit pulse
shape
National bits
(Sa4..Sa8)
Do not change these settings unless
advised to do so by Cisco customer
support, or if you are an experienced
ISDN administrator.
Not all settings apply to all networks.
For example, the National bits are
relevant only for E1 networks.
Video NSF
Telephone NSF
These fields allow you to choose a
value between 1 and 31, or to leave
the Network Specific Facility disabled
(which is the default behavior and the
implied setting in previous releases of
the ISDN Gateway). Do not change
these settings unless advised to do
so by Cisco customer support, or if
you are an experienced ISDN
administrator.
Setting a value adds a field to ISDN
call setup messages which is required
by some ISDN networks. The two
fields allow for networks in which a
different value is required for video
and telephone calls.
ISDN codec settings
Field
Field description
Usage tips
Audio codecs
allowed
Restricts the choice of audio codecs
that endpoints calling through the
ISDN gateway may select. (You
cannot disable the G.711 codec.)
IP and ISDN endpoints negotiate
between themselves which audio
codecs to use during a call. Use these
options if you wish to restrict the
choices available.
Prohibiting audio codecs may prevent
endpoints negotiating a compatible