To improve communication and co-ordination between its emergency services, law enforcement agencies and utilities, the City of Cape Town implemented the first Tetra radio system in Africa in 2001. The contract to replace and manage the city's public safety communications network was awarded to Motorola and Alcom Matomo (a subsidiary of the Altech group).
Background
The City of Cape Town's old analog networks comprised different frequency bands and channels for various departments, which prevented inter-departmental communication and collaboration. In emergency situations, such as fighting the perennial fires on Table Mountain, the lack of an integrated communications network hampered the efficiency of responders.
"We needed a system that could provide instant access in emergency situations; inter-service communications between public safety and municipal departments; low operating costs and also facilitate the consolidation of our call centres," says John Anderson, head of Development and Planning: Radio Services for the City of Cape Town.
The solution
"Tetra technology meets all these requirements due to its reliability and scalability. Being a digital technology, it is less susceptible to interference and provides high quality voice communication. It has the ability to relay vital information directly to those who need it in a variety of formats including data, voice, video and still images. In addition, Tetra's efficient use of the frequency spectrum enhances interoperation between different services while its ability to prioritise resources allows them to be utilised more effectively," he says.
Noel Watermeyer, sales director at Alcom Matomo elaborates: "Public safety and municipal agencies can communicate as one on a single, integrated system that allows the simultaneous transfer of voice and data, improving incident response. Each agency is allocated its own talk group and communication is possible between different talk groups. A 300 millisecond call set-up time allows them to communicate more effectively than traditional or legacy systems."
The Tetra radio system utilises 40 frequency pairs split across the 410-413 MHz and 420-423 MHz frequency bands. It is fully integrated across the entire metropolitan region of the City of Cape Town, enabling some 6500 users to service approximately 3,1 million inhabitants in Cape Town and its surrounds.
Due to the city's mountainous terrain, 22 base station sites were required to provide reliable coverage across the operational area. To handle the predicted traffic, they were equipped with 56 base radios, each one capable of supporting four simultaneous conversations using time division multiple access (TDMA) technology. Central control of resources is achieved through the use of up to 36 separate dispatcher positions.
The result
"The Tetra system has greatly improved efficiency and is being extended to smaller divisions within the municipal council, who previously had to share radio channels and were constantly disturbed by having to listen to communication between other users," Anderson says.
Future plans include using the data capabilities of the network for event management within municipal services. A Technical Operation Centre will capture incoming calls, automatically locate the nearest depot or response team and send a text message directly to their radios. Once the event or incident has been attended to, a status call is logged with the centre, enabling them to monitor efficiency and track the number of incidents.
From a traffic and policing aspect, the intention is to use Tetra's data applications for vehicle tracking and registration identification. This would allow officers to check outstanding fines and identify stolen vehicles on site.
For more information contact Noel Watermeyer, Alcom Matomo, 011 235 7652, www.motorola.com
Fact file
John Anderson, Head: Development & Planning, Radio Services, City of Cape Town, 021 957 4702.
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