P-25 Radio System FAQs

1. What is the P-25 radio system?

As a result of a contract signed by the Lancaster County Board of Commissioners and ARINC on Wednesday, August 1, 2012, the Project 25 (P-25) UHF T-Band Digital Trunked radio system was deployed in 2013.

2. What was included in the original P-25 project?

The project includes upgraded dispatch consoles, core system equipment, tower site equipment, dispatch alphanumeric paging system, and other related equipment associated with the county’s communications center and dispatch capabilities.

3. What is P25?

P-25 is the standard for the design and manufacture of interoperable digital two-way wireless communications products. Developed in North America with state, local and federal representatives and Telecommunications Industry Association (TIA) governance, P-25 has gained worldwide acceptance for public safety, security, public service, and commercial applications.

The published P-25 standards suite is administered by the Telecommunications Industry Association (TIA Mobile and Personal Private Radio Standards Committee TR-8). Radio equipment that demonstrates compliance with P-25 is able to meet a set of minimum requirements to fit the needs of public safety. The P-25 standard was created by and is intended for, public safety professionals. Learn more by viewing the Tait Communications Introduction to P-25 video.

4. What is T-Band?

T-Band is UHF radio frequency spectrum from 470-512 MHz. The FCC made a decision to allocate TV channels 14-20 for use in the public safety sector in larger metropolitan areas. The assignments within this range are typically called T-Band, named for their using the Television Band frequencies for two-way radio communication.

5. What is trunking?

Trunking is a method that utilizes all frequencies within a radio system to its maximum potential. In a trunked system, all radio system users share all the frequencies. When a transmission occurs between two radio system users, the trunked system automatically selects an unused frequency and switches all radios in the system to that frequency. No one radio frequency is assigned to any one department and the frequency could change every time a transmission is made. Instead of talking on a specific radio frequency, as users did on the conventional system, a user in a trunked radio system utilizes “talk groups.”

6. What is the difference between phase 1 and phase 2 P-25 radio systems?

The difference between P25 Phase 1 and Phase 2 radio systems can be explained in simple terms by focusing on how they handle communication and why the Phase 2 upgrade is an improvement:

P25 Phase 1

  • How it works: Phase 1 uses a single channel (frequency) for one conversation at a time. It operates in a system called FDMA (Frequency Division Multiple Access).
  • Analogy: Imagine a single-lane road where only one car can pass at a time. If another car wants to pass, it has to wait.
  • Key Characteristics:
    • Simpler technology.
    • Requires more radio frequencies for multiple conversations.
    • Compatible with older systems.

P25 Phase 2

  • How it works: Phase 2 uses advanced technology called TDMA (Time Division Multiple Access), which splits each channel into two "time slots." This allows two conversations to occur on the same channel simultaneously.
  • Analogy: Think of the same road being turned into a two-way street. Now, two cars can pass at the same time without waiting.
  • Key Characteristics:
    • More efficient use of radio frequencies.
    • Doubles the capacity of the system (can handle more users).
    • Requires updated equipment for compatibility.

Why Phase 2 is Better

  • Efficiency: Phase 2 allows more users to communicate at the same time with fewer frequencies, which is critical when dealing with limited radio spectrum resources.
  • Cost-Effective: Agencies can serve more users without needing additional frequencies.
  • Future-Proof: Phase 2 supports modern technologies and is better equipped for growing communication needs.

In short, Phase 1 is like an older, single-lane system, while Phase 2 is a more efficient, modern two-lane system that handles more traffic at once. Learn more by viewing the Tait Communications Introduction to Phase 1 and Phase 2 Video.

7. Pyramid Repeaters and the new system

Pyramid and Motorola repeaters are authorized on the P-25 UHF T-Band Digital Trunked radio system. Consult LCDPS radio technicians for specific requirements.

8. What radio system coverage can I expect from the new system?

The county requested that the design of the radio system maintain at least 95% reliability, 95% of the time for in-building, on-hip portable radio coverage. In contrast, the conventional radio system was never built as a single system but rather it was a patchwork of radio tower sites with add-ons introduced as needs arose. It was never designed to provide in-building portable radio coverage.

9. Describe communication and interoperability with agencies from other counties?

The network contains interoperability features for units responding into, or out of Lancaster County. Interoperability includes microwave connectivity to the 8-county regional microwave system; authorized sharing of compatible, regional, county talk groups; the ability to patch talk groups together; and the availability of national common talk groups.

10. Who may purchase and use radios on the system?

Only authorized local, county, state, and federal agencies are permitted to purchase and use radios on the system.

11. Where may radio system questions be directed?

Questions can be submitted through the Feedback Form on this website.

12. What can a scanner enthusiast expect from the radio system?

Conventional scanners are not capable of decoding digital voice data. The P-25 UHF T-Band Digital Trunked radio system can be monitored by any scanner that is APCO P-25 Phase 2 capable, or online. Law enforcement talk group audio is encrypted and unable to be monitored.