Radio over IP solutions for the emergency services

Paul Boughton

Radio communications systems for emergency services applications must provide maximum reliability and seamlessly transmit critical messages across networks that include diverse interfaces from multiple vendors. TC Communications has developed a range of industrial radio grade Radio over Internet Protocol (RoIP) products to meet exactly these requirements.

Fire, ambulance and police first responders are often faced with difficulties in maintaining reliable communications with their own dispatch centres, and in sharing information with other emergency services in real time. This can hamper rescue efforts, and potentially put emergency services personnel at increased risk.

Industrial grade radio communication network products from TC Communications for linking or extending 2/4 wire analogue, audio and intercom devices, deliver high quality voice communications combined with maximum system reliability between emergency dispatch centres and remote radio transmitters and receivers.

The TC3846-6 and TC8000 meet the needs of RoIP for emergency services applications. The ‘analogue direct to IP’ functionality means users can preserve existing analogue equipment, migrating 2-wire and 4-wire analogue signals to IP/Ethernet networks without the need to convert for a digital line as an intermediate step. These RoIP products eliminate leased line dependency, utilise existing network infrastructure and increase network transparency. The extremely low latency of 1-3ms enables these products to meet the needs of critical communications applications, while the uncompressed 64K channels means no lost or dropped syllables and more clarity for voting.

The TC3846-6 is an analogue and dry contact Ethernet gateway that can link or extend up to four channels of 600Ω 2/4 wire analogue and dry contacts across Layer 2/3 Ethernet networks. It is simple to configure and supports both point-to-point and point-to-multipoint topologies. The ability of the TC3846-6 to broadcast 4-wire analogue signals over MPLS (multi protocol label switching) means it is the only communications device in its class that is viable for use in public network solutions.

Part of the TC Communications JumboSwitch product family, the TC3846-6 offers a highly versatile analogue radio connectivity solution. It is available either as a standalone product or in a chassis that can support up to 13 other types of interfaces including T1 and legacy interfaces such as modem/fax over IP.

In addition, the TC3846-6 can be used to link or extend other types of analogue, audio and intercom devices such as Frequency Shift Keying [FSK] modems, E&M, teleprotection relay controllers and dry contacts over Layer 2/3 IP networks. It also supports SNV-12 voter/comparator RoIP, picking up the clearest radio signal from field radios and passing it to the intercom. The TC3848 can also provide a virtual PBX to support maintenance phone lines at each tower site.

The TC8000 28-channel analogue fibre multiplexer provides a simple and economical radio tower site solution. Because it uses fibre optic cable rather than phone circuits, it delivers clean and consistent audio signal quality, thus offering improvements on radio dispatch systems that use leased phone lines, which can be susceptible to line distortions and where quality can vary from day to day.

The TC3846-6 and TC8000 support voice bandwidths from 300Hz to 3.4kHz. They feature hot swappable interface cards, offer fibre optic and power redundancy, and are available in extreme temperature versions.