Case Studies:

Northern California County voted radio network preserves legacy equipment with leased line replacement solution


  • Keep essential equipment operational as telcos phase out analog leased lines

Products used


  • Achieved seamless integration with existing equipment
  • Delivered uncompressed 64Kbps analog and dry contact channels
  • Provided minimal latency to work with JPS SNV-12 voters
  • Preserved P25 trunked radio over Ethernet network

Challenge: Replacing expiring leased lines

When a Northern California County realized that telcos were beginning to phase out analog leased lines, they needed a solution, and fast. To keep their essential equipment operational, the county worked to find devices compatible with existing 4-wire analog radios, voters and P25 trunked radio systems. Without this compatibility, they faced increased costs and network downtime. A self-healing ring network also needed to be established to prevent loss of communications between sites. Noting TC Communications' successful completion of a previous project, the county decided again to go with the company's products and solutions.

Solution: TDM over IP

After exploring the options with the technical sales team, they decided to use Ethernet JumboSwitch® cards at each site, thus creating a self-healing Ethernet network. Existing 4-wire analog radios and voters connected to TC3846-6 600 ohm analog and Dry Contact over IP gateways, and the entire migration was done without impacting existing equipment. The TC3846-6 transmits uncompressed 64Kbps audio and dry contact channels with minimal latency and can transmit PTT and COR signals as required by JPS SNV-12 voters.

P25 trunked radio systems connected to T1 lines also needed to be preserved. TC3845-1 T1 over IP gateways were installed to join the P25 trunked radios with the newly established Ethernet network. As a result, the county didn't have to spend additional time migrating legacy equipment for their Ethernet network.

Results: Immediate network cost savings

To keep costs down, the county was able to share fiber with a local broadband company. Between Site A and Site B, the county owned a fiber connection that the broadband company needed. They traded part of their network fibers with the broadband company for use of their Ethernet bandwidth. Through this exchange, the county established a low-cost connection between Site A and Site B that reduced overall costs.

With the solution provided by TC Communications, the county preserved legacy radio equipment while establishing a secure Ethernet backbone for critical radio communications. The County's future plans include adding more sites to the network along with the TCView Network Management System to provide real-time monitoring and control of each JumboSwitch site.