Connect Commercial Displays, Traffic and Passenger Information, CCTV Cameras, and Station Controls Data over SHDSL

Communications networks for rail transportation and highways share similar data collection and transmission requirements and have common network topologies. Low-speed or high-speed data from display panels, surveillance cameras, control equipment, and technician ports are transmitted or collected over a wide geographical area and linked to a central control site. Public address systems and call boxes for emergency voice or technical support may also be connected at different points. Stations or drop-off points are typically linked in a daisy chain or ring configuration.

Although point-to-point wireless equipment may be used in some environments, most networks rely on copper buried along the tracks or asphalt right-of-way. Until recently, low bit-rate data interfaces were the norm for the SCADA equipment and display units dispersed throughout the network. As more and more equipment vendors upgrade their devices to incorporate Ethernet interfaces, however, there is a need to support significantly more bandwidth over the same distances. Laying fiber is an expensive option, but by using SHDSL technology, railway and highway communications engineers can leverage the copper buried in the ground and achieve higher performance over a greater range. RAD’s ASMi-52 and ASMi-52L SHDSL modems can extend the reach of digital interfaces over long distances (up to 10 km or 6.2 miles) and support variable data rates up to 2.3 Mbps over 2-wire and 4.6 Mbps over 4-wire.

The ASMi-52 SHDSL modem comes equipped with an integrated multiplexer, eliminating the need for an external device or additional copper pairs. It can transmit combinations of V.35/X.21/RS-530 data, 10/100BaseT LAN and E1 traffic over a single SHDSL link. The ASMi-52L comes available with a single user port for data or four 10/100BaseT ports with integral switch. All models are compatible with 2/4-wire repeaters, such as RAD's S-RPT, for even longer range applications. The modems also operate opposite RAD's LRS-24 SHDSL modem rack and the company's DXC and Megaplex multiplexer SHDSL modules.

The ASMi-52 is available in a rugged metal enclosure for installation on standard cabinet rail mounts that meet the EN 50121-4 standard.