E F Johnson Company 2425333 Benutzerhandbuch
6-15
SMARTNET / SmartZone / P25 Trunked Features
• The selected scan list can be temporarily changed if the Scan (List) Select option switch
is programmed. The procedure is described in Section 6.11.2.
• In addition to calls on channels in the scan list, pages, private/unit calls, and telephone
calls are received while scanning. Private and telephone calls are not interrupted by
priority messages.
priority messages.
• P25 Trunking allows two Priority talk groups per list.
Every radio on the system has to register with the Zone or Site Controller so that the
system knows where everyone is and if traffic from one site needs to be sent to another
site. This is determined by the list of Talk Groups registered with the radio.
system knows where everyone is and if traffic from one site needs to be sent to another
site. This is determined by the list of Talk Groups registered with the radio.
When a call needs to be passed to a radio at another site, the traffic from one site to
another is then sent out over the control channel to the radios. When a radio is scanning, it
is monitoring the call information being sent out over control channel. The radio compares
the call information (Talk Group and voice channel handling the Talk Group) to the scan
list to see if any of the Talk Groups it is scanning are receiving a call. If it finds a match,
the radio moves to the voice channel for this call. If no one is registered on that Talk
Group on the Site being scanned, the call information for the call is not sent out by the
control channel because the Zone or Site Controller did not see a requirement to pass this
information for this call and the call will not be received.
another is then sent out over the control channel to the radios. When a radio is scanning, it
is monitoring the call information being sent out over control channel. The radio compares
the call information (Talk Group and voice channel handling the Talk Group) to the scan
list to see if any of the Talk Groups it is scanning are receiving a call. If it finds a match,
the radio moves to the voice channel for this call. If no one is registered on that Talk
Group on the Site being scanned, the call information for the call is not sent out by the
control channel because the Zone or Site Controller did not see a requirement to pass this
information for this call and the call will not be received.
For example: Radio 1 is on in a call on talkgroup 1 on Site 1. Radio 2 is on talkgroup 2 on
Site 2 and scanning. The call on talkgroup 1 from radio 1 is not heard by radio 2. Then, if
radio 3 registers on talkgroup 1 on site 2, the call from radio 1 on Site 1 will go to Site 2.
Radio 2, radio 3, and any other radios on site 2 and scanning, will hear the call.
Site 2 and scanning. The call on talkgroup 1 from radio 1 is not heard by radio 2. Then, if
radio 3 registers on talkgroup 1 on site 2, the call from radio 1 on Site 1 will go to Site 2.
Radio 2, radio 3, and any other radios on site 2 and scanning, will hear the call.
6.11.1 Priority Talk Group Sampling
One talk group in the scan list can be designated a priority talk group by programming or
it can be the selected talk group. When scanning, messages on a non-priority talk group
are interrupted by messages on the priority talk group. Priority scanning must also be
supported at the system level for it to occur as programmed in the radio. P25 Trunking
supports dual priority scan, therefore two priority talk groups can be selected.
it can be the selected talk group. When scanning, messages on a non-priority talk group
are interrupted by messages on the priority talk group. Priority scanning must also be
supported at the system level for it to occur as programmed in the radio. P25 Trunking
supports dual priority scan, therefore two priority talk groups can be selected.
The Control Channel handles all traffic for the radios and communicates which talk
groups are using which channels. If the radio “receives” the ID for one of its talk groups, it
can go to that voice channel and hear the talk group. When the radio is ON the voice
channel, it cannot receive information about which talk groups are on which channel. The
radio will not know about any new talk group activity till it finishes the voice channel and
returns to the Control Channel.
groups are using which channels. If the radio “receives” the ID for one of its talk groups, it
can go to that voice channel and hear the talk group. When the radio is ON the voice
channel, it cannot receive information about which talk groups are on which channel. The
radio will not know about any new talk group activity till it finishes the voice channel and
returns to the Control Channel.
If a Talk Group is set as a Priority Monitor talk group on the system, the system sends the
Talk Group’s call information over a voice channel so it can be detected and move to this
priority call. So even if the radio cannot hear the Control Channel, it will receive the call
information and switch to the channel with the priority call.
Talk Group’s call information over a voice channel so it can be detected and move to this
priority call. So even if the radio cannot hear the Control Channel, it will receive the call
information and switch to the channel with the priority call.