Because RFL™ and Hubbell® have a policy of continuous product improvement, we reserve the right to change designs and specifications without notice.
The IMUX Short Haul Fiber module takes three signals from the DS-562NC and multiplexes them
over a single fiber. The signals include transmit and receive timing and transmit data. The receive data
coming from the other fiber is converted to TTL levels for use by the DS-562NC. An activity LED
indicates that data is present on the incoming fiber. There are no jumpers or settings to be made on the
unit.
The outgoing clocks and transmit data are asynchronously sampled at a 2.5 MHz rate generated by an
oscillator. The three resulting bits are put into a serial 8-bit word by a multiplexer. The remaining 5
bits create a fixed pattern which is used by the receiving interface to determine frame alignment. This
pattern is shown below. The serial signal is clocked out at 2.5 MHz and drives the fiber transmitter
DS1.
The receive signal is clocked by the receive timing signal. This data is not modulated and therefore is
passed to the DS-562NC in TTL format exactly as received. The receive data is also used to retrigger a
multivibrator. If no transitions occur within a specified time, the rear panel LED DS2 is extinguished.
3.2 Microseconds
2.5 MHz
0 1 2 3 4 5 6 7
CLOCK
TX FIBER START RX DATA RX TIM. TX TIM. STOP BITS (4) START
DATA
Figure 9. Short Haul Fiber Timing Diagram
RFL DS-562NC RFL Electronics Inc.
July 5, 2012 24 (973) 334-3100
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