Features
• Master / Slave multi-drop system
• Choice of RS-232, RS-422 or RS-485 EIA interfaces
• Bus or Ring system topology with anti-streaming
• Async data rates up to 125 Kbps
• 3–35 km range full-duplex fiber
• Multimode or Singlemode operation over two fibers
• Self-healing and diagnostic display capability
• Compatible with ONS PC-based network
management
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RS-232/422/485 Multi-Drop System
The DS-120MDR multi-drop fiber optical data sets are designed to connect multiple equipment with the RS- 232/422/485 2- or 4-wire interface. The data sets
consist of one Master unit and at least one Slave. Both Master and Slave units provide one port with Async data rates up to 125 Kbps NRZ, and 17/8” x 17” character LCD status display on any remote unit, acheiving full diagnostics with no PC. The Master unit has one optical channel and the Slave unit has two optical channels—A and B.
The DS-120-MDR is ideal for traffic control, industrial process control, and security systems that are configured for bus or ring topologies. The fiber modems regenerate fiber optic signals and provide greater system loss budgets and increased distances.
System Design
The DS120-MDR series is connected to SCADA, ITS, card access systems, CCTV and security host poll equipment through the RS-232/422/485 interface. It transmits the host’s data and control signals on the optical channel to all the Slave units. Each unit has built-in dual power redundancy with alarm back-up battery.
DS-120-MDR-B: In Bus configuration, the Slave unit receives data/control signals from the SCADA host’s channel A, and loops through channel B to the next Slave unit. Slave responds with an RTS signal.
DS-120-MDR-R: In Ring configuration, channel B can be used as a counter-rotating ring. The SCADA host polls every Slave, the Slave responds by an RTS signal, then transmits data/control signals on channel A instead of looping through channel B.
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