User Manual

SGD-SB2025NT-TUM, Part 2
Jan 12 Page 45 SOLAR COMMISSIONING
5.2.1.7 Offset
The ‘Offset’ facility (see Figure 35 below) is provided in order to adjust the relative delay of the
audio output if there is a need to artificially compensate for signal overlap areas that are not
equidistant from sites. The range of delay available is from 0 µs to 255 µs and the required value
is entered directly. An entry that exceeds the maximum will automatically be changed to 255 µs
when applied.
The delay setting is also applied to the CTCSS output if that is used.
Whilst an offset delay may be set on a Central NI it has no effective meaning.
Figure 35. Offset facility.
5.2.1.8 LF Talk Thru
In the event that network communications (line fail) with the TM are lost, setting this facility will
“Enable” Local Station T/T (repeat mode).
Although ‘LF Talk Thru’ may be enabled on a Central NI, it has no meaning.
Figure 36. LF Talk Thru facility.
5.2.1.9 Audio Mode (P25 only)
The ‘Audio Mode’ is only available on a P25 system and can be set to ‘Remote’, ‘Analogue’, ‘P25’
or ‘Auto’. When set to ‘Remote’, the Station NI follows the Audio Mode of the channel it is
assigned to. The Analogue modes are 12.5 kHz and 25 kHz to match the SB2025 bandwidth
setting.
Note.
On a working site, setting the Audio Mode to anything other than ‘Remote’ can end up
with this station being at odds with others on the channel, which can cause a
degradation in overall transmitted signal quality in overlap areas,
Figure 37. Audio Mode facility (P25 only).
5.2.2 Signalling
The input and output signalling, which may be dry contact, tone or a mixture of both, is configured
on the ‘NI Engineering’ ‘Signalling’ page. If this page is viewed through the TM ET there will be a
tab ‘Alarms’ for the ‘Isolated Inputs’ that is not shown on the NI ET – see Section 12 – Alarms for
full details of this function.
The ‘Signalling’ page of the NI Engineering facility is shown overleaf in Figure 38 .