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hector_carbossa
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Interfacing 80's UV VIS
Good Morning.
Very nice forum. This is my first post. I'm a biotechnologist. Unfortunately I'm not omnicomprensive as the associated ideal figure. On the contrary,
sometimes I think this quality wouldn't be strictly necessary, especially in my trials described therefore.
I've an old Carlo Erba UV-VIS spectrophotometer, the spectracomp 602. This and older models, are nowadays anymore used and cited in many scientific
publications. Thus, the temptation of utilizing it in sparetime.
It seems not to miss any internal part, except D2 UV lamp.
It has a rs232 plug and a 50 pin internal parallel plug, I presume for a TTY.
The problem is the total absence of buttons on the instrument. I know (in my fairy world) there are some software that allows data aquisition from
various instruments. I've seen one article with a Perkin Elmer Lambda 2 data seen from Windows XP. Anyway, this software wouldn't allow me to control
the instrument and I doubt more "magic" softwares exist.
When connected to a computer and powered on, serial comunication software don't recognize it.
Obviously, this is my personal troubleshooting flow. Missing a specific software, the only logic way(?). Someone is in the same situation or knows
something useful?
Thanks to all. In any case I hope this argument be worth interesting.
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not_important
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Perhaps someone could get this dcument
| Quote: | Rejuvenating Old Computerized Spectrometric Instrumentation: Discussion of Two Case Histories
Computerized analytical instruments of late 70's and 80's are facing rapid technological obsolescence, although they are often retaining good
analytical performances. Responsibility is to be attributed to the fast advance in computer technology, which is leaving little or no
back-compatibility with old standards and data formats. Rejuvenation may be reached by simple hardware and software modifications, to allow data
exchange with modern PC's and LIMS. Two typical case histories for spectrometric instrumentation of late 70's are then presented and discussed in a
general fashion. |
http://www3.interscience.wiley.com/journal/108061173/abstrac...
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smuv
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Pay it forward
Rejuvenating old computerized spectrometric instrumentation: Discussion of two case histories
Annali di chimica, 2004, vol. 94, no3, pp. 155-163
Attachment: Old_spectros (125kB)
This file has been downloaded 709 times
"Titanium tetrachloride…You sly temptress." --Walter Bishop
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Saerynide
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Haha, I had just asked my university library to get it for me so I could post it... Oh well 
[Edited on 12/1/2008 by Saerynide]
"Microsoft reserves the right at all times to monitor communications on the Service and disclose any information Microsoft deems necessary to...
satisfy any applicable law, regulation or legal process"
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undead_alchemist
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Here is some other info that one university did to interface an old Perkin-Elmer Lambda 3B Spectrophotometer
http://technology.niagarac.on.ca/sop/Lambda3B-SOP-V2.pdf
http://technology.niagarac.on.ca/sop/Lambda3BOperatorsManual...
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hector_carbossa
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Hi and thanks to everyone.
Whole Dossi's publication seems to clarify many hotpoints. I've seen right I've to try with a terminal program. I tried with programs such as
Docklight, DACIO and Bytewedge, but, first to all, I am not so skilled to use them (I'am a biotechnologist). However, no single bit seemed to came
from device to the pc (a 1.2 GHz P3) COMn. I think I've to build an adaptor as the one described. Anyway, my model certainly would be a little recent
than Dossi's. It haven't built-in keyboard but it has a RS232 that I believe missing in the article's 601 model.
I already read latest two documents and I further tried that software without success neither comprension of what I was doing.
I'll try some configurations (including new cables) nonetheless searching more articles in my faculty info lab.
I hope I obtain some results soon. In case of success (or failure), if you're interested, I shall post something worth.
In the meantime I say again thanks to all.
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watson.fawkes
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You might have to exhaustively search through the serial port parameters, trying each in turn, to find out what the defaults of the port on the device
are. Just using COM1 or COM2 isn't enough. You'll have to configure the parameters of baud rate and parity. These change the encoding on the wire, and
if you get the wrong encoding, nothing will transfer, even if the port is actually working.
You may well have cabling issues, particularly if the port uses what's called "hardware flow control", which requires certain non-data wires to have
the correct signals on them. There's an old tool called a breakout box which can be used to experiment with such problems. If you need one, you want
to get one with blinky lights on it so you can see the signals.
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hector_carbossa
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Hi. Today, I changed RS cable with a newer one of the same type. Now I can recognize device with WinDAQ Hardware Manager and obtain a response in
terms of bit received when I send random data with DACIO, but nothing appears there. I tried powering on when I was already connected throuhg terminal
in order to receive all possible data. Conseguentely I've to reboot device everytime to assure nothing is lost.
| Quote: |
You might have to exhaustively search through the serial port parameters |
You're right. I tried at 600 and 1200 bauds. At this time I prospect myself a lot of reboots and fills in a trials table.
I believe that is being a little too intuitive work.
Eluding paranoys, I did my few test with various software but nothing appears I think for this main question.
| Quote: |
You may well have cabling issues |
If I correctly understood, a pin on device may not have match on PC's port. Thus I should use a crossed cable that generally seems more indicated for
non-modem communications. I don't know how old terminal's/pc's RS232 could be changed in twenty years. I'm relatively luckier than Dossi because I
haven't to build an adaptor but perhaps less experienced.
| Quote: |
There's an old tool called a breakout box |
I used a presumable breakout box emulator using two serial ports, TalBreakout. When I turn on the instruments, (nul) string appears and nothing else
happens. What means this? I know this may not be the same thing. However I'll try (this word begins to be persecutory) to get some information about
real tool.
In next step I'll look at crossed cable and nonetheless at some theory.
Thanks again
Goodbye
[Modificato il 2-12-2008 da hector_carbossa]
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watson.fawkes
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I presume you mean this emulator. That will work once you already have cabling working, but it may not be particularly useful in getting the right cable. If you
can't get it working, I do heartily recommend a hardware breakout box.
I should point out that hardware flow control was quite common on old serial ports, back when the electronics to keep up with a "full-rate" serial
connection (9600 bps) was expensive and (hence) not universal. If your equipment is old enough, it almost certainly needs extra signals asserted
before it sends any data out. I can tell you through old experience that it's a real annoyance.
Finally, seeing "(nul) string" is usually an indication that the baud rate is set wrong. It's probably a good sign, because you're at least seeing
something, which means your transmit and receive wires are likely connected correctly.
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not_important
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You'll need to find specs on your particular equipment, to learn exatly what the serial port is.
If the serial interface is RS-232 then generally some futzing with RTS/CTS, and maybe DTR or DCR, is needed; this is the hardware handshaking for
equipment ready and data flow control.
That PDF on rejuvenating old gear states that the Spectracomp 601 spectrophotometer has a built-in 20-mA current loop serial interface. This is not
directly compatible with voltage level RS-232, which is why they built that adapter circuit as an interface between the two.
You can figure this out with an oscope and a few resistors, but the spec sheet might be quicker.
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hector_carbossa
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Hi. Today I changed cable with a crossed one resulting in none results. A thing I havent wrote it's that (nul) came out also when I turn off device.
Obviously, I'll get away from this approach (there are at less 320 different combinations).
Thus, looking at diagnostics I may use BOB or scope but I absolutely don't know what information I can get from there. I think I can see if
effectively there's signal on sending pin. Unfortunately at this time I only have an audio board scope emulator software. I may build a basic probe
connecting sending pin in series with resistor and + mono jack's and - to common ground. At that time, if there won't hardware problems I may see
something as signal or peaks. Thus if timescale's precision shall be affordable I shall use peaks delays to calculate correct baud rate. Starting
resistor may be 20 ohms hypotizing a current less than 50 mA. This method's main problem's I cannot go over 1 V. This workflow I can derive from
mainpoints you stated.
I'll start as soon as possible.
Thanks for suggestions.
[Modificato il 2-12-2008 da hector_carbossa]
[Modificato il 2-12-2008 da hector_carbossa]
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watson.fawkes
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| Quote: | Originally posted by hector_carbossa
Unfortunately at this time I only have an audio board scope emulator software. [...] This method's main problem's I cannot go over 1 V.
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RS-232 is voltage driven, and those voltages typically don't go over 12V. I think the specification allows
up to 24V or so, but I never saw anything over 16V or so. Therefore, make yourself a 25x voltage divider probe and your audio card should work fine.
This requires only a pair of resistors in the ratio 1:24.
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hector_carbossa
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Thanks, this seems better than simple resistor or 5,5 diodes series.
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Sauron
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Well, as you are finding out, RS232 hardware is not all created equal and you really need them pinout for your unit and the correct matching cable. I
have run up against this hassle before with older Waters serial controlled PDA UV detectors, like models 990 and 991, which were controlled by a
dedicated Fujitsu (as I recall) PC running an elderly DOS of the IBM flavor (PC-DOS) and software written by a company still extent in the HPLC column
business. The machine was controlled by two special proprietary RS232 cards installed in ISA slots in the PC and connected by cables to the detector.
I had the detector, but no old PC, no cables, and no special boards. I did manage to obtain the software and correct version of PC-DOS and get it
running on an old HDD. But lacking the cards and cables...
LabView of course could be of no help, it was a lost cause.
Sic gorgeamus a los subjectatus nunc.
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hector_carbossa
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Hi.
Scope test: preliminary setups for decent scopic data retrieval.
Random test: A thing I have forgotten for long time that previous unknown user shortened pins 2 and 4 with a piece of metal wire. What did it means?
And what is effective use of "Terminal" 25+25 parallel port?
| Quote: |
RS232 hardware is not all created equal |
No datasheet exists. So I've now random pining in best case.
| Quote: |
The machine was controlled by two special proprietary RS232 cards installed in ISA slots |
Some things may be not all-in-one. This may happen.
I don't know your instrument's year. Mine's 1984's.
However I mantain expectations because it probably has built-in microcomputer which only processes, sends data and receive simple commands. Previous
model has this setup according to Dossi's work.
The only thing to do now is optimizing the scope test.
I also may use win NT I already have on test's PC.
Broken microcomputer should be an hypothesis to take in consideration at certain point.
In effect there's a gambling component.
Goodbye.
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not_important
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| Quote: | Originally posted by hector_carbossa
Hi.
Scope test: preliminary setups for decent scopic data retrieval.
Random test: A thing I have forgotten for long time that previous unknown user shortened pins 2 and 4 with a piece of metal wire. What did it means?
And what is effective use of "Terminal" 25+25 parallel port?
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This doesn't sound like standard RS-232/DTE/DB-25, for which pin 2 is transmitted data and pin 4 is RTS, which often would be tied to CTS (pin 5).
RTS/CTS is a common hardware handshake flow control, connecting them together at each device generally allows the port to operate with no hardware
handshaking, and thus no need to run wires for those pins. Connecting TD to RTS akes little sense.
You may need to figure out the interface part of the port hardware, to determine what the pinout is and if it is RS-232, current loop, or something
else.
I'm not understanding your last question.
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hector_carbossa
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Sorry, perhaps I misexplained. I've DB9 on device such as on PC. Thus tx should be pin 3 and tx "must" send anything and effectively do it but I
couldn't recognize signal structure due to software's saving function lacking.
Other connector is substantially blue one you can find on LPT1 printers, but has two linear arrays of 25 pins for total 50 pins.
With probability them are these.
Only now I realize it may be dedicated terminal or telewriter cable. However DB9 should be necessary for real computer controlling. But I recommend
you taking this information with pliers.
Dossi adapted pre-RS232 to DB25 using just txs and rxs. I need in my case, only DB9 cable. So I thought there may only to set right configuration. But
this is only an hypothesis.
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Sauron
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The connector I am talking about was DB-37
Waters used/uses same connector for power cable between controller and HPLC pumps in the 600 analystical and also the preparative series, they look
like a "standard" PC cable but not so as they are quite special. Waters sells these cables for about $500 US. I have several of them. The ones for the
600s are not same as the ones for the prepLCs. Not interoperable.
The serial control cable for the 990/991 Waters PDA looked same but no telling what the pinout was. (No original cable to reverse engineer.) I have
several of them.
Not at all like your little DB9.
Sic gorgeamus a los subjectatus nunc.
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hector_carbossa
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Today, unable to find signal logger I opened device for looking at wires colors.
From left to right I annoted upper pins:
1: green/yellow (tipically ground colors)
2: violet
3: white/orange
4: blue
5: yellow
6, 7, 8 and 9 are unused. This induce to think configuration may be simple as in Dossi's publication: send, receive, rts and cts or something similar.
At this time seems better I follow hardware approach.
This was most simple trial from beginning. Now I may build very simple BOB with 25 ohm-led in parallel with 1 ohm and connecting each to random match
(most intuitive) on PC's port that should be on basal signal.
This It's only hypothesis but the most promising.
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watson.fawkes
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Typical buffer chips for that generation of equipment were the 74LS244 and 74LS245, whose inputs and outputs would be directly connected to the port.
They were typically socketed because they had a tendency to blow out. The color code on the wires is without meaning; there was no standard. On the
other hand, if you trace out the connector pins to (presumably) the pins on the IC's where they connect, you may be able to determine, with the help
of a data sheet, which are the inputs and which are the outputs.
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hector_carbossa
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Ok. I used simply quite resistant boxy shaped leds. I turn on PC, then I turn on device.
I noted this (real numbering):
5: nothing
4: permanent light until I turn on (CTS?DTR?)
3: permanent light when I turn on. (RTS?DSR?)
2: nothing
1: nothing
I don't know signal on 4. When I turn on, pin 3 transmits RTS signal (logical 0 or 00000000 also I seek with binary port manager).
Pin 1 and 2 should be tested to find transmit and receive. 1 with probability is ground.
At this point I may think test connection like this:
5 --> 5
4 --> 8
3 --> 7
2 --> 2 or 3
1 --> 3 or 2
Here it's obvious it isn't standard. I tried with 5(5) 4(8) 3(7) 2(2) 3(3). It doesn't work with every cable. Now I have to try various combinations.
Nonetheless I may try repeating BOB test for each pin to ground.
UPDATE
In last trials, no combination seems useful. I extracted I/O board but I haven't found those chips. There are four long AMD's chips named P8255APC or
something similar. However seems impossible to get pinout by this way.
However in I/O board there are some switchs for baud rate selection from 75 to 4800. At this point new combination trial with correct speed is
required.
Another thing it's I obtain (nul) in each configuration. Naturally I tried all configurations with 5(5).
I don't know if 80's microcomputers have a BIOS but I'll check battery if there's one
Goodbye
[Modificato il 6-12-2008 da hector_carbossa]
[Modificato il 6-12-2008 da hector_carbossa]
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watson.fawkes
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The P8255APC is an 8255A "programmable peripheral interface" chip. See the Wikipedia page. Each chip does 8 bits of data, for a total of 32 bits total. My guess is that those 50 pin connectors (so-called Centronics
connectors) are some kind of daisy-chained laboratory bus, so that two of the 8255A's are dedicated to upstream and two to downstream. In any case,
these chips weren't used for serial port interfacing.
The buffer chips I mentioned are much smaller. They're 20-pin DIP chips. Other buffer chips were used, though; I mentioned the ones I recall. If you
can trace out the IC pins that the serial port pins connect to, it might well tell you which of your pins are inputs and which are outputs.
At a maximum of 4800 baud, you will definitely have to get the hardware flow control working. With five pins, it looks like you have 1 ground, 1 Tx, 1
Rx, 1 each flow control in/out. You're likely right that pin 1 is signal ground; that was typical. As for the others, I don't know.
It's typical for gear to send out a "hello message" when it turns on. You will probably have to enable flow control to see this. (A hint: at 75 baud,
you can see the individual bits on the breakout box. They're fast, but distinctive.) For the purposes of debugging, you can tie the appropriate pin
either high or low (it might be either). Tie a pin low by connecting it to ground with just a wire; tie a pin high by connecting it to +5V with a 10K
resistor.
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hector_carbossa
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Hi. At bottom of this post there are results (not all) with at 75-110 baud setting. I recognized with two antiparallel leds in series with each pin. I
noted no single bit flowing perhaps sensorial precision may be influent (or I have to trash everything).
Because it's impossible negate that results list reading may be boring I can condens it here in principal current flows (first's devpin, second(s)
crossed cable pins)
2 from 7, 8
3 to 3 (COM's 2)
3 from 4 an 2 (COM's 3)
3 to 7 when on
3 from 8 when off
4 from 7 when on
4 from 8 always
1 from 8 more when turn on
3 to 5 when off
This excluding single pulses in opposite flows. I omitted here, but already tested, connections with COM's ground, that results always in low glowing
except for pin 3 that's brightest.
I would prefer table but there's no way to make decent one (all combos are Device Pin - COM Pin):
2-7 onin continuous signal
out single pulse
offin maybe pulse
out maybe pulse
2-8 onin continuous low signal
out nothing
offin continuous low
out nothing
3-2 onin nothing
out continuous signal
offin nothing
out nothing
3-3 onin single pulse
out continuous signal
offin nothing (pulse when turn off)
out nothing (pulse when turn off)
3-4 onin continuous signal
out single pulse
offin s.p. when t. off
out s.p. when t. off
3-5 onin nothing
out nothing
offin nothing
out nothing
3-7 onin single pulse
out continuous signal
offin s.p. when t. off
out s.p. when t. off
3-8 onin nothing
out nothing
offin continuous signal
out nothing
4-1 onin nothing
out nothing
offin nothing
out nothing
4-2 onin nothing
out nothing
offin nothing
out nothing
4-3 onin single pulse
out single pulse
offin s.p. when t. off
out s.p. when t. off
4-4 onin nothing
out nothing
offin nothing
out continuous pulse
4-5 onin nothing
out nothing
offin nothing
out nothing
4-7 onin continuous
out single pulse
offin lights off
out s. pulse
4-8 onin continuous
out nothing
offin continuous
out nothing
1-7 onin very low light
out nothing
offin nothing
out nothing
1-8 onin continuous
out nothing
offin lower continuous
out nothing
[Modificato il 6-12-2008 da hector_carbossa]
[Modificato il 6-12-2008 da hector_carbossa]
[Modificato il 6-12-2008 da hector_carbossa]
[Modificato il 6-12-2008 da hector_carbossa]
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hector_carbossa
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Draw back to simpleness, but not to defeat, I used again one of that programs that should monitor COM ports. I used one in which some virtual leds
called DSR, CD, CTS and RI.
One only pin activate CTS indicator. Another pin activate either DSR and CD (I think in crossed cable they are shorted). It's also possible to check a
box called DTR but I think now I came in new field.
I haven't seen bits with leds nor with programs (except logic 0 on some ports).
Some combinations with ground, presumable CTS and presumable DSR at right positions and remaining T and R at right speed don't work. Only my ignorance
supports me to go forward (an naturally your hints). Why? A thing I don't know is how work non data cables in overall protocol. I noted continuous
signal, that may be right due to its presence on same COM port's position.
At this point, having minimum combination, I have to know what may be wrong with software so I returned to parameters trouble. Last thing I think is
theresn't no data for a question of "authorization" to send. Now I remembered an "inverse" trial I performed in firts few tests. Port's signals are
different when I turn them listening. Thus, opening port when device is already initialized may be needed event (if I havent burnt all in the
meantime).
Contrarily to routine in which devices has to be connected to pc ready to recognize them, pc (or "dumb" terminal) as to be connected to device. Device
is the computer.
Just to break eggs in my chest I noted nothing appears when, sometimes I closed and reopened port.
Due to my inphormatic's lacks I can't discrimine any informationless situation from a situation that prepare me to being a rare gold plated
integrated's merchant (this is dreaming reality I imagine to buffer mental status soon I'll be condemned to).
In effects, who suggested to leave all wasn't completely wrong. Fact is I already left all some months ago. This is "the final challenge". Time to
kick RS232's "luck" hasn't came yet (at this point only shifted).
Goodbye
[Modificato il 7-12-2008 da hector_carbossa]
[Modificato il 7-12-2008 da hector_carbossa]
[Modificato il 7-12-2008 da hector_carbossa]
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watson.fawkes
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The trial where you got "continuous pulse" is likely one where your unit was sending on boot.
Also, if you're using LED's and can scrounge up a 5V power supply, you can test the unit in isolation without using a serial port. It's a matter of
tying various pins high and low and looking for data pulses. After you've determined where the Rx and CTS pins (receiver data and control) are, making
a cable is a matter of looking up the pinout for the other side.
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