RAD's SHDSL Modems Enable Tramway Passengers to Buy Tickets With Credit Cards

When Augsburg Verkehrs GmbH, the public utility company in the Bavarian city of Augsburg, decided to offer tramway passengers the convenience of paying for their tickets with a debit or credit card, they selected an advanced SHDSL solution from RAD Data Communications to connect ticket vending machines to an online system.

The solution, based on RAD’s ASMi-52 modems and LRS-24 modem racks, was supplied by SCALTEL, one of RAD's German distributors.

Mobile or SHDSL Technology?
The first decision that the authorities in Augsburg had to make was to select the appropriate technology, a choice between mobile communications and DSL. A mobile communication solution would have been much more expensive, since the ticket machines would have had to have been linked to the central office over a GSM network using dial-up modems. Given that the city's public utilities company already owned its own copper and fiber data network, the decision was quickly made in favor of DSL, which required only a one-time investment. In addition, DSL's permanent online connection makes disruptions controllable and guarantees high transmission reliability. The type of DSL was also chosen quickly. “Due to the long distances that needed to be covered and the high demands made on transmission reliability, SHDSL technology was the only alternative,” explained Marcel Vogl, Pre-Sales Manager at SCALTEL. Another decisive advantage of this technology is its resistance to the electromagnetic fields that can be produced by the high-tension wires used as the tramway's overhead lines.

The SHDSL access solution connects 136 ticket machines at the streetcar stops via existing copper lines over the company's fiber-based Metro Area Network. Up to 18 ticket machines in any one area of the city combine to form eleven cells. RAD’s ASMi-52 modems use a point-to-point DSL line to connect each ticket machine in a cell. Depending on the distance – a maximum of ten kilometers – a two-wire or four-wire configuration is used. A RAD LRS- 24 rack equipped with ASMi-52 dual/quad modem cards picks up the DSL lines and forwards the data to an Ethernet switch. The switch then bundles this information and transmits it via a RAD ETX-22 media converter to the core network. RADview SNMP-based graphical element management software enables easy system monitoring as well as performance testing and guarantees high performance reliability.