Snom ONE IP Technical Manual page 72

Deploying the snom ONE IP Telephone System
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Allow domain admin to change dial plans: This feature allows the adminis-
trator to hide all dial plans from domain administrators. When this feature is
set to No, domain administrators will be unable to change or view dial plans.
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Allow domain admin to create or change accounts: If this feature is set to
No, domain administrators cannot create, change, or view accounts.
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Allow domain admin to create or change ANI: If this feature is set to No,
domain administrators cannot create or change the ANI (automatic number
identification). The ANI is used when the system sends an outbound call on a
trunk (see page 95 for more information on the default ANI).
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Loopback detection: This setting applies only to multi-domain environ-
ments (for single-domain environments, leave this setting on). When the
system starts a call, that same call may come back to the system and create a
loop. This may happen if the call is made to another caller on the system in
a multi-tenant environment. This is a dangerous situation because it might
repeatedly initiate the same call, ending up in many calls that take a lot of re-
sources. Therefore, the system must detect such a loop. In environments where
an external SIP proxy routes the call from one snom ONE domain to another,
a simple loopback detection that is based on the call-ID is too pessimistic.
Therefore, in such environments, you might want to allow these calls and turn
the loopback detection off (see the Try Loopback setting on page 155).
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Inband DTMF detection: When a user presses a key on the telephone, the
system must be able to understand the action. In telephony systems, this
mechanism is typically called DTMF. In VoIP, DTMF is usually sent "out of
band" (RFC 2833) because it allows the system to easily detect the tones in a
fail-safe manner. However, not all devices support this method, and when this
is the case, the system must decode and analyze the media stream and perform
this detection. Because this is erroneous and costs additional CPU perfor-
mance, it is strongly recommended that you not use this feature and instead
replace devices which do not support the out-of-band method with devices
that do. In-band and out-of-band can be compared to a T1 line that uses in-
band signalling and a PRI line that uses out-of-band signalling.
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Remote SIP management: This setting allows the provider to send com-
mands to the system (for example, for rereading the configuration). It is useful
in environments where the service provider controls the system from a central-