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Dymec Links & Stars
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  • FAQ--Serial Links
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  • Serial Links

    Can I use a 232 link with a 485 link?

    • Yes, but the 485 link must be set for INV logic.

    Problem with copper connection...

    • Transmit and receive wires reversed
    • Using chassis ground when it should be signal common

    Everything is wired correctly but it still doesn't work...

    • Fiber connected in reverse
    • Reflection due to fiber length
    • Wrong type of fiber
    • Poorly terminated connectors on fiber
    • Fibers not properly seated in the link connectors
    • Trying to overextend the maximum distance
    • Baud rate is too high
    • IEDs are not operating at the same data rate
    • Wrong voltage powering the link
    • Connecting to a non-compatible, non-Dymec Link fiber converter
    • Using a 232 link on a 2-wire 485 port or vise-versa
    • Network requires handshaking, and unit doesn't support it
    • Polling is constant so light on/off cannot be differentiated

    232 Links

    • DCE or DTE switch in wrong position
    • REP or OFF switch in wrong position

    422/485 Links

    • NOR or INV switch in wrong position
    • HD or FD switch in wrong position
    • REP or OFF switch in wrong position

    Problems with loop configuration...

    • Master cannot accept/filter its own poll packet
    • Repeat switches are not all set correctly
    • Trying to use an Optical Star in the loop
    • Connecting to another brand of fiber converter

    Problems with bus configuration...

    • Each copper segment of the bus not terminated on both ends
    • Transmit and receive fibers crossed in the network
    • Too much noise due to long copper wire lengths
    • More than 3 devices on a 485 bus may cause a problem due to the biasing resistors

    Ethernet Links

    • Either the crossover port or the straight through port can be used, not both
    • Cannot connect a 10 Base unit to a 100 Base unit
    • Cannot be used with our Serial Links