Specifications

TD 92326GB
2009-03-10 / Ver. E
Installation and Operation Manual
VoIP Gateway
157
22.8 Dial tones
The VoIP Gateway is able to generate call progress tones at the ISDN interfaces (dial tone,
ring tone, busy tone).
This is done for outgoing calls from the VoIP Gateway in the direction of the calling party,
whenever the called party does not generate any dial tones of its own.
For incoming calls at the ISDN interface, this is usually only done in the direction of the
calling party if the interface is in NT mode, not however if it is in TE mode. In a few cases
though, in particular when linking up PBXs via tie lines, it can be useful to also generate
these tones in TE mode. This can be done using the “Provide inband call progress tones”
setting.
22.9 Define Source for Time and Date
The VoIP Gateway does not have a battery-backed real-time clock. The internal time will
thus be reset to 0:00 hrs, 1.1.1970 after every restart.
The correct time is not required for normal operation. However, if this is important to you,
to get, for example call detail records with the correct time, you can specify the IP address
of a source for time and date. The VoIP Gateway will then synchronise its internal clock to
the time source at intervals specified.
You can use a public server if your network does not have an NTP server. The TU Berlin, for
example, provides a time service under the IP address 130.149.17.21. Bear in mind that it
is a voluntary service and no claims can be made with regard to its availability
Note: Every Windows 2000 server can work as an SNTP server. Equally, there are freely
available SNTP software packages for Windows and Unix/Linux platforms.
The VoIP Gateway also operates at the same time as an NTP server. If you are operating
additional gateways, you can synchronise one of them with a time server (external if
required) and then in turn synchronise the other ones with it.
Further public time services can be found worldwide on the Internet under http:/ /
www.eecis.udel.edu/~mills/ntp/.
If you are operating other devices in your network that require a time server (for example
further gateways or VoIP clients), please enter the IP address of your VoIP Gateway there.
Your VoIP Gateway will then operate as the time service and signal the correct time to the
other devices. Avoid synchronising all devices with one external time service, since this
results in unnecessary high loads on these servers.
Time services always provide the coordinated world time (Universal Time Coordinated
[UTC] which corresponds to Greenwich Mean Time [GMT]), not however the correct time
zones and summer time. You can therefore specify the time difference between your time
zone and the universal time in the String field. The difference from the time zone GMT+1
(Central European time zone) is 60 minutes. A further 60 minutes has to be added with
summer time, adding up to a total difference of 120 minutes. In this case however, you
must adjust the time difference manually when switching from winter to summer time
and vice versa.
This setting can be automatically made by the device if you specify the “Timezone” field.
The name of the time zone, the name of the summer time zone, their respective
Tip: Dial tones can be identified by the “inband information”, which is signalled by the
called party.