SOFTWARE GATEWAY FOR P25 TRUNKED RADIO
P25 CSSI gateway software for trunked radio dispatch
omniGateP25 is a software gateway that connects dispatch consoles to a P25 trunked radio system over one CSSI connection – up to 256 talk paths, P25 Phase 1 and Phase 2, on a server or virtual machine.
Standards-based CSSI
Standard P25 CSSI for trunked systems, plus every radio vendor Omnitronics supports through IPR and DRG hardware gateways.
256 talk paths
One CSSI connection carries every talk path, with 12, 24 or 48 simultaneous conversations per gateway.
Phase 1 and Phase 2
Works with P25 Phase 1 FDMA and Phase 2 TDMA trunked systems.
Interoperability certified
Certified on the Tait P25 TN9400 system under the Tait Technology Partner Program.
The challenge
Why dispatching P25 through one gateway per CSSI link gets expensive
A P25 trunked system talks to dispatch through the Console Subsystem Interface (CSSI). When every hardware gateway needs its own CSSI connection, each extra talk group or console position adds another box, another license and another link to maintain.
Control rooms end up sizing dispatch around gateway ports instead of the operators and talk groups they actually need. Growth means new hardware, and new hardware means another project.
How it works
How omniGateP25 connects your consoles to the P25 core
omniGateP25 registers with your P25 radio frequency subsystem (RFSS) as a console subsystem, then presents each talk group to your consoles as a talk path.
One CSSI connection
A single CSSI link to your home RFSS carries every talk path. If the home RFSS stops responding, the gateway switches to a secondary RFSS automatically.
A talk path per talk group
Configure up to 256 talk paths. Up to 256 console connections share each talk path, using a single vocoder stream however many consoles are listening.
Consoles connect over SIP
omnicore consoles connect over SIP and RTP. Third-party consoles, voice recorders and a SIP PBX can join the same talk paths.
What you get
More dispatch capacity from the P25 system you already run
Everyone gets the same core benefit: more consoles and talk groups on one CSSI connection, with failover built in and no gateway hardware to rack for each link.
For operators
- Every console sees the same talk groups, unit IDs, emergency calls and status messages.
- AES-256 and DES encryption, with keys loaded from a key loader.
- P25 Tier 1 and Tier 2 location on the console map, including on-demand GPS requests.
- Pre-recorded emergency announcements and tones broadcast to chosen talk groups, triggered by a radio, a status message or the web interface.
- Automatic failover to a hot-standby gateway, with talk group selections kept in sync between the pair.
For resellers and integrators
- Works with every radio vendor Omnitronics supports, over CSSI or through Omnitronics IPR and DRG hardware gateways.
- Simultaneous conversations licensed at 12, 24 or 48 per gateway – add a gateway instance when a site needs more.
- Deploys on a fan-less industrial PC, a rack server or the customer's own hypervisor.
- A documented path for replacing Tait TAG deployments (application note).
- Browser-based configuration, SNMP monitoring and backup and restore, so day-to-day administration needs no Linux skills.
- Backed by Omnitronics support and omnicare maintenance plans.
Overview
What is a P25 CSSI gateway?
A P25 CSSI gateway connects dispatch consoles to a P25 trunked radio system through the standard Console Subsystem Interface. omniGateP25 does this in software, carrying up to 256 talk paths over one CSSI connection so every console can reach every talk group without a hardware gateway per link. For background on the standard P25 interfaces, see the ISSI and CSSI primer from CISA's SAFECOM program.
Built on the P25 standard
CSSI is the P25 interface between a trunked system's RF subsystem and its console subsystem, and a subset of the Inter-RF Subsystem Interface (ISSI). Over it, omniGateP25 supports group, individual, broadcast and system (All Call) calls, call alert, emergency and emergency clear, status messages, radio check, stun, revive and remote monitor. A Phase 1 (FDMA) compatibility mode covers systems that don't support Phase 2.
Encryption, location and emergency messaging
Talk paths can be encrypted with AES-256 or DES, with keys loaded into the gateway from a key loader. P25 Tier 1 (NMEA) and Tier 2 (LRRP) location puts radio positions on the console map, and dispatchers can request a location on demand. Emergency annunciation broadcasts pre-encoded messages and tones to chosen talk groups without tying up vocoder capacity. A talk group monitor mode shares one monitored talk group across many console talk paths while transcoding it only once.
Resilience
Two gateways run as a hot-standby pair: the standby takes over if the active gateway, its network or its RFSS connection fails, and talk group selections stay synchronized between them. Omnitronics recommends placing the standby at a second site.
Every radio vendor Omnitronics supports
Because omniGateP25 also connects to Omnitronics IPR and DRG hardware gateways, it reaches the analog and digital radio systems Omnitronics supports – see the technology logos at the foot of this page. Consoles see those channels alongside the P25 talk groups, and dispatchers can patch between them.
Deployment
The gateway runs on Ubuntu Server, on a fan-less industrial PC, a rack server or as a virtual machine on Hyper-V, VMware or Proxmox. Its software vocoder needs a host processor with AVX2, passed through to the guest.
Key facts
- Interface: P25 CSSI to trunked systems, Phase 1 and Phase 2
- Capacity: up to 256 talk paths; 12, 24 or 48 simultaneous conversations per gateway, with more gateway instances for higher capacity
- Consoles: up to 256 console connections per talk path
- Console support: omnicore and third-party SIP or RTP consoles
- Radio systems: standards-based P25 CSSI trunked systems, plus the other radio systems Omnitronics supports through Omnitronics IPR and DRG hardware gateways
- Encryption: AES-256 and DES, loaded from a key loader
- Location: P25 Tier 1 (NMEA) and Tier 2 (LRRP)
- Resilience: hot-standby gateway pair and secondary RFSS
- Platform: Ubuntu Server on a fan-less PC, rack server or virtual machine (AVX2 required)
- Certification: Tait Technology Partner Program on the Tait P25 TN9400 system, July 2025
FAQ
omniGateP25 questions buyers ask
How many talk paths and calls does it support?
omniGateP25 supports up to 256 talk paths over one CSSI connection. Each gateway supports 12, 24 or 48 simultaneous active conversations, depending on the license. Where a site needs more than 48, additional gateway instances are deployed.
Does it work with P25 Phase 2 systems?
Yes. omniGateP25 works with P25 Phase 1 FDMA and Phase 2 TDMA trunked systems. A Phase 1 compatibility mode is available for RFSS equipment that supports Phase 1 only.
Can it run on a virtual machine?
Yes. omniGateP25 runs on Ubuntu Server as a virtual machine on Hyper-V, VMware or Proxmox, on a rack server or on a fan-less industrial PC. The host processor must support AVX2 and the hypervisor must pass it through to the guest, because the software vocoder relies on it.
Which consoles can connect?
omnicore consoles connect to omniGateP25 over SIP, with up to 256 console connections per talk path. Third-party consoles, voice recorders and SIP PBX systems can connect using standard SIP or RTP.
Which P25 systems does it work with?
omniGateP25 connects to P25 trunked systems over the standard Console Subsystem Interface (CSSI), Phase 1 and Phase 2, rather than a vendor-specific link. Through Omnitronics IPR and DRG hardware gateways it also reaches the other radio systems Omnitronics supports. Its interoperability has been certified on the Tait P25 TN9400 system under the Tait Technology Partner Program.
Can it replace a Tait TAG?
Yes. Omnitronics publishes an application note on using omniGateP25 in place of a Tait TAG to connect dispatch to a Tait P25 trunked system. Talk to our team about your current configuration to plan the move.
Related
Build out your P25 dispatch system
Pair omniGateP25 with omnicore Enterprise Dispatch Management System for the console side. Conventional P25 repeaters connect through omniGateP25DFSI, and Airbus Agnet broadband users join P25 talk groups through omniGateAIR.
Compare every option on the software RoIP gateways overview, read the interoperability certification announcement or see how Omnitronics supports public safety dispatch.
Put every P25 talk group on every console
Tell us about your P25 system, talk groups and console positions, and we'll size omniGateP25 for it.
Reseller or integrator? Become an Omnitronics partner and bring it to your customers.
