Transnet, the parent company of South-Africa-based Transtel, bills itself as a "transporter of people, goods and information." Holdings include railways, airlines for passengers and cargo, ports, road transport, pipelines, and highways for information as well.

Transtel is the information technology arm of the Transnet Group, running a telecommunications network with customers in 16 African countries and an annual turnover of about US$100 million. The network carries mostly voice traffic, with 50,000 subscribers, along with packet data including some Internet connectivity. The network is composed of fibre, microwave, mobile radio, and a satellite component. On the satellite side, Transtel is full service provider. Network design, installation, project management, integration, training and 24/7 network operations are available to its customers.

The satellite portion of the network, called Spacelink, is used mainly for international trunking of long distance telephone calls. About 300 sites are outfitted with ViaSat Skylinx and SkyRelay satellite terminals, with an IP overlay in some locations. A network operations and control hub is in Johannesburg, SA. Each site has a total of four to eight channel units, with seven or eight voice channels multiplexed into 64 kbps circuits.

In this part of the world, the wide-ranging locations within the network cannot be covered by a single C-band satellite footprint. As a result the ViaSat networking equipment operates on both PanAmSat 10 at C-band and Intelsat 704 at Ku-band. The Johannesburg hub includes both 11-meter C-band and 9-meter Ku-band antennas, also supplied by ViaSat.

Where VSAT is used, the key reason is the flexiblity of the system. Not only does it carry traffic even to remote locations, but it provides an infrastructure that can adapt wherever it goes.

"We can customize our network using the modular ViaSat VSATs," said Andre DuToit IT director at Transtel. "We can build the network and connections around the application. It also gives us a quick and affordable path to future upgrades as well."

That flexibility is illustrated by Transtel customers, including banks, railways, retail stores, other local telcos, and some civil and security networking. Traffic on the network is a mix of dedicated and demand assigned (DAMA) links, depending on the requirements of each customer. Telcos connect their voice traffic mostly by dedicated SCPC links that remain busy carrying phone calls, but some terminals operate in MCPC DAMA mode for bandwidth efficiency in circuits with more intermittent traffic. Banking customers use the opposite mix, with SCPC circuits for voice and DAMA for data. Retailers and the railways both use DAMA to connect remote locations to central databases.

Regulations continue to be a challenge in South Africa. Telkom SA, the terrestrial carrier is privatizing, but is still in control of local wireless landing rights. As a result Transtel must operate gateways in both London and Botswana. In those locations it brings the satellite traffic to the ground and then link it to the local network in South Africa by terrestrial means.

But with privatization and more liberal regulation coming, DuToit feels Africa is one market where VSATs have a long future. The low population density is ideally served by satellite, and for the same reason next generation spot-beam Ka-band systems will not penetrate the market for many years. To secure its place in the growing market, Transtel will be one of a group of companies forming a second network operator for South Africa. They will team with Esi-Tel, BEE, and one additional foreign equity partner.

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