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.

Conventional Trunked
Radio channels selected by the user Radio channels assigned to the user automatically
Channel access instantaneous Channel access time varies with technology and other factors (typically measured in hundreds of milliseconds)
No control channel needed Control channel used in all P25 trunked applications.
Suitable for smaller groups of users Better for larger (~300+) organizations
Switching not needed Core switching essential for operation
Digital control signaling inherent Digital 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.

Feature P25 Conventional P25 Trunked
IP backbone Available Available
Analog and digital operation (repeaters/subscribers) Yes/yes No/yes
Simplex/half-duplex/duplex (repeaters) Yes/yes/yes Half duplex/duplex
Access Control/subscriber registration Yes Yes
Supports analog and digital consoles Yes Yes
Dispatch console support Analog and digital Analog and digital
End-to-end encryption Yes Yes
Distributed, centralized or switched voting Yes Yes
Simulcast Yes Yes
Multisite(automatic roaming) Yes Yes
Self-calibration (simulcast) Yes Yes
Rx voting Yes Yes
Multi-site switching Distributed/centralized Centralized/distributed
Advanced remote monitoring and diagnostics Yes Yes
Analog line interface Yes Yes
MDC1200 interface support Yes Yes
Multiple linking options including RF Yes Yes (stricter requirements)
OTAR Yes Yes
Packet data support Yes Yes
Voice call types Group, individual, announcement, broadcast, emergency
Non-voice call types All standardized P25 supplementary services – status, radio check, monitor, call alert, inhibit/uninhibit, short message
Talk Group ID Yes Yes
Individual ID Yes Yes
Emergency ID Yes Yes
Emergency Alarm Yes Yes
Call addressing Yes Yes
Cancel P25 Unit Call (dispatcher interrupt) Yes Yes
Automatic working channel assignment (trunking) No Yes
Talk group scanning Yes Yes
Late entry Yes (limited) Yes
Call queuing No Yes

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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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