What do I need to consider to permit multiple portable and mobile radio vendors on a P25 System?
This is ultimately up to the system operator, but in general, radios must operate in the frequency band used for the system. In addition, the subscriber unit features offered should be compared to the features required within the system. When offered features match required features, requesting interoperability test data from the specific manufacturers is recommended. Project 25 Phase 1 FDMA and Phase 2 TDMA Subscriber compatibility and Interoperability for different vendors and different software revision levels can be confirmed using CAP test data found on the DHS website https://www.dhs.gov/science-and-technology/p25-cap
Contact potential vendors to confirm their position on interoperability with other P25 products and systems.
Best results for interoperability and sharing occur when the radios are programmed to offer common channel/Talk group names and zone architecture. Enabled features should be consistent when possible; all features do not have to be offered to all user groups.
Are there any examples of P25 systems on the air today with multiple vendor subscriber units approved for operation on the system?
PTIG members have identified more than 3300+ (Conventional and Trunked) P25 Systems on the air today, and more are in the planning stage. Many have multiple vendors’ P25 subscriber units approved for use on their systems. Alaska, Wyoming, Michigan, Connecticut, Pennsylvania, New
Mexico, Ohio, Dallas/Fort Worth, The City of Wichita, and Lancaster County PA are just a few examples of systems using multiple vendor subscriber units.
I currently am on a conventional analog system. A new P25 trunking system is available in my area. What choices do I have for subscriber units that will work with both analog and P25?
Project 25 subscriber units typically include backward compatibility to analog operation.
If your system and the P25 system are in the same frequency band you can choose a single band radio. P25 Multi band radios multi-mode radios are available for interoperability between systems with different frequency bands (example 700/800 MHz trunking to VHF 136-174 MHz conventional).
In addition, Interoperability products can create hard patches between conventional analog and P25 trunking. Other network vendors also support mapping from conventional to trunking user groups without patching. See the PTIG WEB project25.org Products Tab:
https://www.project25.org/index.php/products/p25-supplier-matrix for a full range of solutions.
Why do we have a P25 system but my system operator says we can only buy one brand of radio?
The P25 Common Air Interface supports interoperability between the RFSS and Subscriber Units from different manufacturers. Furthermore, there are numerous examples of deployed P25 systems that offer choice in P25 subscribers. Of course, specific subscribers available on each system are dependent on operator policy.
Many agencies are currently operating with products from multiple vendors on the open P25 Standard. There are 15 infrastructure suppliers and 14 subscriber unit suppliers building Project 25 equipment. If you can buy only one brand it may be because it is the policy of your system operator based on the economics of maintaining multiple brands of equipment. Or it may be that you have manufacturer specific features or capabilities in your system that are offered by only one vendor and are not covered by the Project 25 suite of standards.
Are there any examples of P25 system infrastructure from different vendors linked to make a single system?
Yes. Examples include a Dallas/Fort Worth 7 MHz “overlay” that uses multiple vendors’ subsystems linked using the P25 ISSI interface. A number of similar deployments are in place or in planning including in Connecticut, Florida, Oklahoma, Denver Region and Southern Texas.
If I have one manufacturer’s P25 trunked RF Subsystem (RFSS), can I use a different manufacturer’s consoles?
Yes, if your RFSS includes a Console Subsystem Interface (CSSI). As long as the RF and the console manufacturer’s systems both support the P25 CSSI standard, you can pick whichever RFSS and Console System that best suits your needs. However, it is prudent to consult with both manufacturers to verify: if the requested console is supported, if the system will support it, if there is capacity, and if testing has been completed to verify the supported P25 features. Note that some radio system manufacturers may implement non-standard features to consider.
Are there real-life examples of P25 Trunked RF Subsystems from one manufacturer being connected to a console system of another manufacturer using the P25 CSSI?
Yes, P25 manufacturers have implemented the P25 CSSI to connect a console system to P25 trunked networks. Many P25 deployments in the United States and around the globe have implemented this integration. The P25 CAP website is the best place to find products that are compliant with P25 CSSI equipment testing.
If I am connecting to a single manufacturer’s P25 Conventional RF Subsystem (RFSS) or Conventional Console Subsystem (CSS) can I connect a base station or repeater from a different manufacturer?
Yes, if your RFSS/CSS provides a Conventional Fixed Station Host and the Fixed Station manufacturer supports the Fixed Station Interface (FSI). See TIA-102.BAHA – Fixed Station Interface for further information.
