<div>Hi David,</div> <div> </div> <div>See if this is what u're looking for<BR><A href="http://ronja.twibright.com/technotes/how.php">http://ronja.twibright.com/technotes/how.php</A><BR><B><I></I></B></div> <div><I><STRONG>Plus heres some explanation i found in a report by</STRONG><FONT face=TimesNewRomanPS-BoldMT></div> <div align=left><STRONG>CHANCEY, MARK ALAN</STRONG></FONT><FONT face=TimesNewRomanPSMT>. Short Range Underwater Optical Communication Links.</FONT></div> <div align=left> </div> <div align=left>The original document is in pdf, so sorry if the block diagrams are missing.</div> <div align=left><FONT face=TimesNewRomanPSMT><STRONG></STRONG> </div></FONT></I><I><FONT face=TimesNewRomanPS-BoldMT> <div align=left><STRONG>UTP – </STRONG></FONT><FONT face=TimesNewRomanPSMT>The UTP (Universal Twisted Pair) is the main interface to the PC. The signal from</div> <div align=left><STRONG>the RJ-45 port goes into the RJ-45 Filter. The
schematic below shows the pin layout of the</STRONG></div> <div align=left><STRONG>RJ-45 filter. This filter isolates the board from outside noise. The RJ-45 standard calls for</STRONG></div> <div align=left><STRONG>twisted pair wires consisting of a positive and negative wire for the transmit and receive, for</STRONG></div> <div align=left><STRONG>a total of 4 wires. This differential output setup is used to reduce any noise the Ethernet</STRONG></div> <div align=left><STRONG>cable may receive from outside sources. The positive and negative transmit signal are on</STRONG></div> <div align=left><STRONG>pins 9 and 11 of the filter. The respective receiver pins are 14 and 16. This can be seen in</STRONG></div> <div align=left><STRONG>the schematic below. The signal is then passed into the transmitter circuit of the UTP.</STRONG></div> <div align=left><STRONG></STRONG> </div> <div align=left><STRONG></STRONG> </div></FONT><FONT face=TimesNewRomanPS-BoldMT>
<div align=left><STRONG>TX Circuit</STRONG></FONT><FONT face=TimesNewRomanPSMT>– The transmitter establishes the handshaking between the idle signal and the data</div> <div align=left><STRONG>stream in preparation to be sent to the LED transmission board.</STRONG></div> <div align=left><STRONG>- </STRONG></FONT><FONT face=TimesNewRomanPS-BoldMT><STRONG>MC3486 (Quad Differential Line Receiver) </STRONG></FONT><FONT face=TimesNewRomanPSMT><STRONG>– This IC multiplexes the two differential</STRONG></div> <div align=left><STRONG>transmission signals (positive and negative) into one signal.</STRONG></div> <div align=left><STRONG>- </STRONG></FONT><FONT face=TimesNewRomanPS-BoldMT><STRONG>74HC74N (Dual D-Type Flip-Flop w/ Set and Reset) </STRONG></FONT><FONT face=TimesNewRomanPSMT><STRONG>– This IC provides a 1MHz idle</STRONG></div> <div align=left><STRONG>signal for the LED. This signal is for maintaining a defined DC level and to prevent</STRONG></div> <div
align=left><STRONG>receiver noise and unwanted signals from being amplified in the limiter on the receiver</STRONG></div> <div align=left><STRONG>board. The system would not work without the 1MHz signal. Packets would be randomly</STRONG></div> <div align=left><STRONG>lost due to received packet echoes from the opposite direction on shorter links, sometimes</STRONG></div> <div align=left><STRONG>even on longer links due to random noise resembling a preamble, and most importantly,</STRONG></div> <div align=left><STRONG>the remaining packet would not be received at all because the corrupted preamble would</STRONG></div> <div align=left><STRONG>be received by the RJ-45 interface.</STRONG></div> <div align=left><STRONG>- </STRONG></FONT><FONT face=TimesNewRomanPS-BoldMT><STRONG>74HC14N (Hex Inverting Schmitt Trigger) and 74HC132N (Quad Schmitt Trigger</STRONG></div> <div align=left><STRONG>NAND Gate) </STRONG></FONT><FONT face=TimesNewRomanPSMT>– These ICs work together
to decide if the idle signal or data signal should</div> <div align=left><STRONG>be passed. If no packet is detected, the idle signal is passed. When a data signal is</STRONG></div> <div align=left><STRONG>detected, the idle signal is dropped. The red indicator LED on the board is flashed to</STRONG></div> <div align=left><STRONG>indicate transmission activity.</STRONG></div> <div align=left><STRONG></STRONG> </div></FONT><FONT face=TimesNewRomanPS-BoldMT> <div align=left><STRONG>RX Circuit </STRONG></FONT><FONT face=TimesNewRomanPSMT>- This circuit filters out the 1MHz signal, passes the data signal to a demultiplexer,</div> <div align=left><STRONG>passes the (positive and negative) signals to the RJ-45 filter which then passes</STRONG></div> <div align=left><STRONG>them to their respective receive wires on the RJ-45 port.</STRONG></div> <div align=left><STRONG>- </STRONG></FONT><FONT face=TimesNewRomanPS-BoldMT><STRONG>74HC74N (Dual D-Type Flip-Flop w/ Set
and Reset) </STRONG></FONT><FONT face=TimesNewRomanPSMT><STRONG>– Produces Ethernet standard</STRONG></div> <div align=left><STRONG>250Hz (NLP or Normal Link Pulse) signal which tells the PC the UTP is an Ethernet</STRONG></div> <div align=left><STRONG>compatible device. Every 4ms this NLP is sent to the PC maintaining the compatibility</STRONG></div> <div align=left><STRONG>status.</STRONG></div> <div align=left><STRONG>- </STRONG></FONT><FONT face=TimesNewRomanPS-BoldMT><STRONG>Common Emitter Pair </STRONG></FONT><FONT face=TimesNewRomanPSMT><STRONG>– Pre-amplifier for incoming ~700mVpp to ~4Vpp. This</STRONG></div> <div align=left><STRONG>increases the current and voltage so that incoming pulse train will trigger the input of the</STRONG></div> <div align=left><STRONG>74HC14N.</STRONG></div> <div align=left><STRONG>- </STRONG></FONT><FONT face=TimesNewRomanPS-BoldMT><STRONG>74HC14N (Hex Inverting Schmitt Trigger) and 74HC132N (Quad Schmitt Trigger</STRONG></div>
<div align=left><STRONG>NAND Gate) </STRONG></FONT><FONT face=TimesNewRomanPSMT>– Rejects the 1MHz idle signal so that it is not passed to the PC. If a data</div> <div align=left><STRONG>signal is detected it passes the signal, otherwise the 250Hz NLP is sent to the PC for the</STRONG></div> <div align=left><STRONG>reasons described above. The green indicator LED on the board flashes to indicate</STRONG></div> <div align=left><STRONG>reception activity.</STRONG></div></FONT><FONT face=TimesNewRomanPSMT size=4> <div align=left><STRONG>- </STRONG></FONT><FONT face=TimesNewRomanPS-BoldMT size=3><STRONG>MC3487 (Quad Differential Line Driver) </STRONG></FONT><FONT face=TimesNewRomanPSMT><STRONG><FONT size=3>– This IC de-multiplexes the incoming data</FONT></STRONG></div> <div align=left><STRONG>signal into separate differential output (positive and negative) receive signals for the RJ-</STRONG></div> <div align=left><STRONG>45 filter and port.</STRONG></div></FONT><FONT
face=TimesNewRomanPS-BoldMT size=4> <div align=left><STRONG>Transmitter</STRONG></div></FONT><FONT face=TimesNewRomanPS-BoldMT size=2> <div align=left><STRONG>Figure 5-18 Functional block diagram of the transmitter board, Right) The transmitter circuit. Full</STRONG></div> <div align=left><STRONG>circuit diagram in Appendix B.</STRONG></div></FONT><FONT face=TimesNewRomanPSMT> <div align=left><STRONG></STRONG> </div> <div align=left><STRONG>The signal arrives via the coaxial connection. The DC filter removes any DC offset, which</STRONG></div> <div align=left><STRONG>leaves a pure square wave. Before the signal is transmitted, the signal must be current</STRONG></div> <div align=left><STRONG>amplified to push the LED. This is accomplished by an emitter coupled transistor pair</STRONG></div> <div align=left><STRONG>(preamp) and by stacking three 74HC04 ICs. The signal is then ready for transmission via</STRONG></div> <div align=left><STRONG>the cyan
LED.</STRONG></div></FONT><FONT face=TimesNewRomanPS-BoldMT size=4> <div align=left><STRONG>Receiver</STRONG></div></FONT><FONT face=TimesNewRomanPS-BoldMT size=2> <div align=left><STRONG>Figure 5-19 Functional block diagram of the receiver board, Right) The receiver circuit. Full circuit</STRONG></div> <div align=left><STRONG>diagram in Appendix B</STRONG></div></FONT><FONT face=TimesNewRomanPSMT> <div align=left><STRONG>The receiver detects the photons via the photo detector. The low current signal triggers a</STRONG></div> <div align=left><STRONG>dual gate transistor (NTE415) which takes the current from the 12V rail and transmits it to</STRONG></div> <div align=left><STRONG>the NE592 video amplifier. The NE592 cleans the incoming rounded signal to a square</STRONG></div> <div align=left><STRONG>wave. Pin 7 of the NE592 is part of a differential output which is used to measure the signal</STRONG></div> <div align=left><STRONG>strength based on the alignment of
the optical signal. This is called the received signal</STRONG></div> <div align=left><STRONG>strength indicator (RSSI). Pin 8 of the NE592 is the other part of the differential output and</STRONG></div> <div align=left><STRONG>carries the data stream through a pre-amp/limiter circuit consisting of a pair of common</STRONG></div> <div align=left><STRONG>emitter connected transistors which limits the signal to ~700mVpp. The signal is then sent to</STRONG></div> <div align=left><STRONG>the receiving end of the UTP.</STRONG></div> <div align=left><STRONG></STRONG> </div> <div align=left><STRONG>Hope this helps,</STRONG></div> <div align=left><STRONG></STRONG> </div> <div align=left><STRONG>Saad</STRONG></div></FONT><FONT face=TimesNewRomanPS-BoldMT size=4> <div align=left> </div> <div align=left></FONT></I> </div> <BLOCKQUOTE class=replbq style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #1010ff 2px solid">Hello.<BR><BR>I am a student at
a school in the United States and I'm trying to build the <BR>Ronja Inferno by myself. I'm breaking up the project into parts and I am <BR>currently working on the Twister2 Module. I have two boards fabricated and <BR>am working on soldering parts.<BR><BR>I am wondering if there is anyone on this list that would be willing to give <BR>some guidance in what I'm doing because at my school I don't have many <BR>resources.<BR><BR>As a side question, would anyone be able to direct me to a resource that <BR>explains how the data goes from simple computer data packets and then to <BR>light and then back to computer data packets?<BR><BR>Thank you,<BR>-David<BR><BR><BR><BR>-- <BR>Twibright Ronja mailing list http://ronja.twibright.com<BR>Ronja@lists.pointless.net<BR>http://pointless.net/mailman/listinfo/ronja<BR></BLOCKQUOTE><BR><p> 
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