Advanced Capabilities

Scalable Links: The Internet Protocol supports millions of addresses.  Mobile radio users can take advantage of this architecture to keep adding more IP Link Gateways to the community.  While some hardware-based solutions limit the number of agencies that can potentially be part of a patch, an IP-based solution does not.

Cost-Effective Connectivity: This architecture eliminates dedicated circuits for routing radio traffic.  The routed audio and control can share the same data pipe with email, database inquiries, file transfers, and other computer network applications. Thus a separate connection for routing occasional radio voice messages between agencies is not required. Installing microwave radios or dedicated fiber is a huge capital expense. Leasing telephone circuits presents an expensive recurring expense. The IP computer network has become the universal transport media for telephony, data, video, and now radio voice traffic.  This single pipe approach is being adopted by municipalities, federal agencies, and corporations worldwide as the most cost-effective approach to communications.

The needs for interoperability are diverse and unpredictable.  There are too many agencies to justify funding point-to-point circuits between each.  Only the IP network can provide flexible, cost-effective connectivity for the variety of links needed to face today's challenges.

Robust Links: IP connectivity is not only cost-effective; it can also provide a more robust link.  IP networks allow for alternate routing of packets.  If a dedicated circuit is broken, radio connectivity is lost completely.  If a packet-switched connection is broken, the IP packets can be re-routed along another path.

Similarly, a centralized switch for interoperability presents a single point of failure.  If that hardware device becomes inoperable then all connectivity is lost.  On the other hand, the IP-based network approach distributes the routing function across many devices, significantly increasing the likelihood that the message will get through.

Peer-to-Peer Interoperability: IP Link allows each agency to set up and tear down a patch with any other willing agency.  Each agency is a peer.  There is no central switch or central over-ride.  Each Gateway can be individually set to allow patches or not allow patches. Thus the supervisor for each agency makes the final decision if his agency will participate.  Since all agencies are peers there is no need to request a patch from a third party. If two agencies want to create a patch, they simply do so directly.  Since each Gateway may only be a member of one patch at a time, by consenting to being part of a patch, the supervisor blocks other agencies from bringing his Gateway into a different patch. Since only those dispatchers with access to a Gateway can modify a patch including that Gateway, the patch is restricted to a pre-defined community.

Get the First Syllable: The first syllable can often be the most critical part of a message. There's a big difference between "shoot" and "don't shoot."  Some interoperability solutions lose that critical first syllable because they use a VOX circuit. Other times syllables or even words are lost because the secondary system takes times to get access to a channel. (Trunking systems can take from 250 ms to tens of seconds to provide channel access.) Important messages are lost in the process.

IP Link buffers the voice message until the secondary system is ready to play it. VOX circuitry is not used in IP Link. The radio Gateway stores the packets from the last call that came across the network until the attached radio is ready to transmit that message. Thus if the secondary system is a trunked system that takes a full second to provide channel access for the desired talk group, then the radio Gateway will wait the full second to send the voice message so that the trunked system can transmit the entire call. Similarly, if the trunked system is busy with another call and queues the attached radio,
the radio Gateway will continue to store that voice message until there is a free channel.