Conventional or Trunked P25?

Deciding on P25 is not the end of the technology selection process: important choices need to be made. Conventional or trunked? Phase 1 or Phase 2?

Luckily, in most cases these decisions are not difficult. While you should use an experienced consultant to guide your decision, some simple rules of thumb can help you in this area.

Conventional or trunked?
First, we can dispense with the misconception that there is a large functional gap between P25 conventional and trunked systems. This is not the case. The table clearly sets out the main functional differences.

ConventionalTrunked
Radio channels selected by the userRadio channels assigned to the user automatically
Channel access instantaneousChannel access time varies with technology and other factors (typically measured in hundreds of milliseconds)
No control channel neededControl channel used in all P25 trunked applications.
Suitable for smaller groups of usersBetter for larger (~300+) organizations
Switching not neededCore switching essential for operation
Digital control signaling inherentDigital control signaling inherent

Conventional vs. trunked feature comparison
Based on this information, as long as you have sufficient channels for the number of users and the number of user groups, you will save money and effort by staying with P25 conventional architecture.

FeatureP25 ConventionalP25 Trunked
IP backboneAvailableAvailable
Analog and digital operation (repeaters/subscribers)Yes/yesNo/yes
Simplex/half-duplex/duplex (repeaters)Yes/yes/yesHalf duplex/duplex
Access Control/subscriber registrationYesYes
Supports analog and digital consolesYesYes
Dispatch console supportAnalog and digitalAnalog and digital
End-to-end encryptionYesYes
Distributed, centralized or switched votingYesYes
SimulcastYesYes
Multisite(automatic roaming)YesYes
Self-calibration (simulcast)YesYes
Rx votingYesYes
Multi-site switchingDistributed/centralizedCentralized/distributed
Advanced remote monitoring and diagnosticsYesYes
Analog line interfaceYesYes
MDC1200 interface supportYesYes
Multiple linking options including RFYesYes (stricter requirements)
OTARYesYes
Packet data supportYesYes
Voice call typesGroup, individual, announcement, broadcast, emergency
Non-voice call typesAll standardized P25 supplementary services – status, radio check, monitor, call alert, inhibit/uninhibit, short message
Talk Group IDYesYes
Individual IDYesYes
Emergency IDYesYes
Emergency AlarmYesYes
Call addressingYesYes
Cancel P25 Unit Call (dispatcher interrupt)YesYes
Automatic working channel assignment (trunking)NoYes
Talk group scanningYesYes
InterfacesISSI, PSTN, DFSISSI, PSTN, CSSI
Late entryYes (limited)Yes
Call queuingNoYes

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Specifying your P25 System: Articles

2 responses to “Conventional or Trunked P25?”

  1. […] differences between trunked and conventional systems are summarized in the following articles • Technology Selection conventional or trunked P25: • Trunked vs. Conventional – Some […]

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