Ned Soseman /
04.15.2011 08:00 AM
Originally featured on BroadcastEngineering.com
Sencore develops solution for PBS to support the WARN Act
Sencore has partnered with PBS to create a customized groomer solution, the Sencore Transport Data Injector (TDI 3000). The TDI 3000 provides insertion of emergency message data to support PBS’ participation in the Warning, Alert, and Response Network (WARN) Act across the United States.
Passed by Congress in 2006, the WARN Act establishes a system for cellular providers to transmit emergency messages such as presidential alerts, imminent threats and Amber Alerts. The FCC's Commercial Mobile Alert System (CMAS), established in 2008, enables cell phone service providers to receive WARN emergency messages that are then formatted for 90-character text message retransmission to cell phones. In addition, the FCC requires PBS member stations to act as a backup transmission path for WARN by carrying message data in their broadcast transport streams, from which the cell provider gateways may extract the messages if the primary link to FEMA becomes unavailable.
Sencore's TDI 3000 plays a "groomer" role in the WARN system by receiving messages via satellite feed from PBS and then injecting them safely into the local broadcast stream within five minutes of their arrival, without affecting broadcast service. Redundant TDI 3000 units are installed at most PBS member stations, operating between the production system and the ATSC modulator. An independent antenna and receiver from the PBS satellite feed brings the WARN message into the station's operation, where it is passed to the TDI 3000 via ASI or IP transport stream. The TDI 3000 uses a packet restamping scheme to avoid remultiplexing the affiliate transport stream, and it does not change video or audio services or otherwise modify the primary multiplex. Null packets are used whenever possible to inject the WARN messages.