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RADIO NETWORK TRUNKING
Introduction
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MPT 1327 - What is it?
• MPT 1327 is one of many
specifications relating to
radio equipment for use in
the United Kingdom. (MPT
stands for Ministry of Post
and Telecommunications)
• The standard details the
operation of an automatic
trunked radio network using
conventional narrow band
FM radio channels.
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Radio Trunking
• What is meant by trunking?
• Trunking is the sharing of resources
• All available channels are utilised to the best advantage.
• Applied to radio systems, this means the sharing of available
radio channels.
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Conventional Radio System
Repeater Tf1 Rf2
Repeater Tf3 Rf4
Repeater Tf5 Rf6
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Trunked Radio System
Repeater Tf1 Rf2
Fylde
TSC
FYLDE
TSC
Repeater Tf3 Rf4
SIO BUS
Fylde TSC
Repeater Tf5 Rf6
Fylde TSC
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Conventional Vs
MPT Trunked Systems
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Efficient utilisation of frequencies.
Automatic supervision of all calls
Greater immunity to system failures
Increased facilities
Larger range of compatible radio equipment
(compared to selective calling systems)
• Simplicity of Operation
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System Access
– Conventional Radio
• Channel must be monitored for activity. Co-Channel
users must clear before the next call is made.
– Trunked Radio
• In the Fylde MPT trunked radio systems the required
party identity is selected by the calling party and the call
is initiated, with the system then taking control and
connecting the call onto a free talk channel.
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Privacy
– Conventional Radio
• Privacy is not fully possible as all users can share the
same RF channel. Privacy is not practical as the channel
is monitored for access when free. Coded squelch can be
used to reduce over talking.
– Trunked Radio
• Users in a call have exclusive use of the talk channel for
the duration of the call. Only the call parties are tuned to
the RF talk channel. It is also possible to provide speech
encryption on the radio network.
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Trunked Radio System Benefits
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Efficient use of the RF spectrum
Privacy
Advisory system status messages
Automatic call connections
Subscriber call authorisation
Call limit timing and management
Automatic system fail soft and standby
mechanisms
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Fylde MPT System Facilities
• Local and Intersite speech and status calls.
• Local and optionally Inter-site group speech
and short data calls.
• Inter-fleet and Inter-prefix calls.
• Radio to PABX/PSTN and PABX/PSTN to
radio unit speech calls.
• Call diversion.
• Non Prescribed Data messages.
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Fylde System Management
Facilities
• Variable individual and user group facilities,
coverage areas and priorities.
• Dynamic call timers on a time and day of week
programmable basis.
• Call billing and traffic statistics.
• Remote alarm and maintenance facilities.
(all above facilities require SCI and SYSCON)
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Supported Call Types
• Speech Calls
– Mobile to mobile
– Mobile to PABX
– Mobile to PSTN
• Status calls (pre-defined status codes)
• Short Data
– Messages up to 23 chars (GPS Systems)
• Long Data
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Plus....
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AVLS
Call Diversion
Group Calls
Called in absence
Pre-emptive Emergency Calls
Priority Calls
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