Thanks Brian. Turns out your cable links weren't in my
thread at all. They were in a different thread completely
which I wasn't part of, and wasn't following.
Here's the situation. Those two cables you recommend in
that other thread are null modem cables. Fine - but I've
already learned the problem I have is with my usb/serial
cable. Soon as I plug it into the 102, the 102 screen dims,
which may be caused (I've been told) by crossed wiring in
that cable.
So, even if I do buy another cable (one of the null modem
cables), I'd still need some kind of usb/serial
"converter/adapter". There's no usb on the recommended null
modem cables, and there's no serial port on the Dell laptop
or desktop.
Thanks.
Tom M.
On Wed, Apr 10, 2019 at 12:39 PM Brian White
<bw.al...@gmail.com <mailto:bw.al...@gmail.com>> wrote:
In one post, I provided a link directly to two items, a
specific cables2go cable and a specific sabrent
usb-serial adapter, so that you wouldn't have to make
sense of the full page where that info came from.
And also linked that full page, which includes the
startech and others.
http://tandy.wiki/Model_100_102_200_600_Serial_Cable
I know reading that full page might not make 100% sense,
because it's a lot of verbiage, and there are many
cables listed there and they all work for this so how do
you choose, and some parts are kind of cryptic, which is
why I pulled out the two parts to get.
For instance the shorthand I used to document each
cables wiring idiosyncracies, like "DCD<>DSR+DTR", I
know that part is cryptic. When I was testing cables and
assembling the info, I just needed to get the key
details written down, and the form didn't matter. I
could expand it to be more readable later.
What those little things are showing is how each
particular cable differs from the rs232 spec.
For instance "DCD<>DSR+DTR" means that dsr and dtr are
tied together on one end, and connected to dcd on the
other end, and that it's the same on both ends in both
directions. All other connections are according to the
rs232 spec, and you get the pin numbers and positions
from the rs232 spec.
Some time when I want to spend more time on that page, I
can expand those to a less cryptic form, (or anyone else
can, it' s a wiki) but until then at least the knowledge
is documented so that later I can refer to it. It's sort
of like working notes until then.
Mike Stein also provided a direct link to a specific
monoprice cable. That one is good too. (it's on that
page too for instance)
All other cables you randomly find from wherever,
probably aren't right without some kind of adapters, and
there is no way to tell if the wiring is right except by
knowing the rs232 spec and testing the connections.
rs232 is not a single thing, it's a spec with a bunch of
options and configurations. In order to use anything
serial, you the user, actually has to understand that
spec, or, you have to take the word of someone else who
does, and says "this specific cable will work for this
specific application". Plugging in any old cable without
knowing how it's wired or what the different rs232
signals are for and how they work, will never work.
Serial is not like usb or ethernet or headphones.
For another example of ehat I mean, even when you
finally get a correct serial cable for connecting your
m100 to a pc, that cable won't be correct for connecting
to a modem, or a plotter, etc. 3 different devices, 3
different cables, and yet all of them are valid correct
serial cables even though they are all different from
each other.
The only way to make it work is to understand that and
go read about serial cables so that you know enough that
you could build your own from scratch, or continuity
test any off the shelf cable to fully understand what it
does. Or, buy one that is already known to be correct
for this particular task.
--
bkw
On Wed, Apr 10, 2019, 7:30 AM Thomas Morehouse
<nutmegfl...@gmail.com <mailto:nutmegfl...@gmail.com>>
wrote:
Brian - you wrote:
"
The Cables2Go one I linked is all the same, except
it also has rts/cts,
so it works with HTERM, as well as everything else.
And finally, the StarTech one I linked, is also all
the same, but
without shorting DCD to DSR, or shorting DTR to DSR,
which means that
one should cause the least possible drain on any
possibly weak power
rails in the M100.
All this mystery has already been completely figured
out and nailed
down. One mouse click and $7 later and you're done."
I've gone through all your posts in this thread, and
find no links for Cables2go or StarTech.
I'm absolutely going nuts here, trying to figure out
how to do things, and how to follow advice. One
post with advice raises a question, someone else
tries to answer the question, then someone else
tries to clarify the answer to someone else's
question. Really helpful to some, but frustrating to me.
Which post had those two links for the proper
cables? I've now got two usb/serial cables which
don't seem to work, plus several male/male,
female/female, and DB9 to DB25 adapters. Total so
far: $100.
As I can't find the links Brian referred to, I don't
want to guess and buy yet another thing which might
not work.
Thanks.
Tom M.
On Tue, Apr 9, 2019 at 9:34 PM Kurt McCullum
<ku...@fastmail.com <mailto:ku...@fastmail.com>> wrote:
Tom,
Looks like you will need to either build or buy
a cable. My two cents is below but I'm sure
others will chime in. There are several options
out there.
Here is a description of what I do with all my
Model-T units. I start with this DB25 to DB9
adapter which is just a regular DB9 to DB25
converter. I attach these with some 2.5mm
(should be 2.6mm) screws to the Model-T so its
always attached.
https://www.sfcable.com/db9-female-to-db25-male-serial-mini-adapter.html
Then I put one of these adapters in between the
DB9 serial port and the 9-25 adapter which
creates a null modem cable.
https://www.sfcable.com/null-modem-adapter-db9-db25/db9-male-to-female-null-modem-mini-adapter.html
For my T200 I have remove pin 1 from the null
modem adapter to make it happy but that's a
quick fix with needle nose pliers.
Everybody has there preference on cable setup so
eventually you will come up with a solution that
works for you. Sounds like what you have is
working for text transfers so that's a start.
Kurt
On Tue, Apr 9, 2019, at 5:59 PM, Thomas
Morehouse wrote:
Thanks Kurt.
Testing the DB9-DB25 adapter only - not the
usb/serial cable - I have continuity NOT from
pin 4 of the DB9 to pin 6 of the DB25. I have
continuity from pin 4 of the DB9 to pin 20 of
the DB25. That's using the numbers printed at
the pins themselves.
Should I even bother testing the others you
suggest? Sounds like the adapter already fails
the test.
Tom M.
On Tue, Apr 9, 2019 at 8:48 PM Kurt McCullum
<ku...@fastmail.com
<mailto:ku...@fastmail.com>> wrote:
Ignore the USB to serial piece of the
puzzle. As Brian said, it's just a serial
port. Test the 9 to 25 adapter. One end
will be female so it's easier to put
something like the end of a paper clip into
one hole at a time then put the probe on that.
Kurt
On Tue, Apr 9, 2019, at 5:22 PM, Thomas
Morehouse wrote:
OK - looks like I wasn't clear. In Kurt's
post, he writes:
"Take one probe of the meter and put it on
pin 4 of the DB9 and the other on pin 6 of
the DB25. It should beep or light up
(however you meter functions to indicate a
connection). Then do the same for the DSR
line on pin 6 to pin 20. And finally the
RTS and CTS pins 7->5 and 8-> 4. If they
are crossed in some manner, then you will
not get a beep or a light."
If the usb/serial cable is a single unit
(usb at one end, DB9 at the other), how do
I put one probe of the meter on the DB9
and the other probe of the meter on the
DB25? There's no DB25 on the cable,
unless I plug the 9-25 adapter into the
DB9 - but then I can't put a probe on the
DB9. Jeez I feel dense.
I'm really sorry I can't follow this, but
maybe I'm just overlooking something
really simple?
Thanks.
Tom M.
On Tue, Apr 9, 2019 at 7:56 PM Brian K.
White <bw.al...@gmail.com
<mailto:bw.al...@gmail.com>> wrote:
You don't check continuity on the
usb-serial adapter. That isn't just a
cable, it's really a peripheral like a
disk drive or a printer, it just
happens to be a peripheral that all
fits entirely inside the plug
housing on one end of it. There is no
simple direct wire mapping between
the usb pins and the serial pins.
Between the usb pins and the serial
pins, there is circuit board with a
chip and a few other components
which is converting and translatine
between two entirely different kinds
of signals and protocols.
You treat the usb-serial adapter as
just a serial *port*, and ignore
that it looks like a wire. Just
pretend it's like a serial port built in
to the back of an old desktop.
You check the continuity of the serial
cable, which IS "just a cable".
Or, really, you check the continuity
of the combined serial cable with
any null-modem and gender-changer
adapters, and treat that all together
as one "cable".
--
bkw
On 4/9/19 6:56 PM, Thomas Morehouse wrote:
> Thanks Kurt. I'm even denser than
usual tonight I guess.
>
> From earlier posts, seems the
problem (102 screen dimming) is likely
> caused by the usb/serial cable. One
end of the cable is a usb plug;
> other end is the DB9.
>
> So I'm afraid I don't know how to
test continuity on the cable. I can
> find pin 4 of the DB9 - but where
does the DB25 fit in the picture?
>
> Or, are you saying to test the cable
with the DB9/DB25 adapter plugged
> into the cable?
>
> Sorry to be the dolt again.
> Tom M.
>
>
> On Tue, Apr 9, 2019 at 10:57 AM Kurt
McCullum <ku...@fastmail.com
<mailto:ku...@fastmail.com>
> <mailto:ku...@fastmail.com
<mailto:ku...@fastmail.com>>> wrote:
>
> There are store bought cables
that work well. Brian has done a
> great job putting together a
list of those cables. For my machines
> I have a mixture of custom made
cables or slim adapters. Both
> methods work and give me the
pinout below. When you get the cable
> right, your M102 will be happy.
>
> But to the question at hand,
don't tear apart your cable. Check
> it. Right now you know that pins
2,3 and 5 are all going to the
> right locations. You will need
to check pins 4,6,7 and 8. Since
> those are paired lines (4/6,
7/8) one or both pairs will be flipped.
>
> If you have a multi-meter which
has a continuity check on it then
> you test both ends of the wire.
>
> Here is what I have found to
work on all my machines and I include
> this in the mComm manual.
>
> 7 Wire Cable
> PC
>
> Model-T
> DCD
> 1
> NC
>
>
> RX
> 2
> →
> 2
> TX
> TX
> 3
> ←
> 3
> RX
> DTR
> 4
> ←
> 6
> DSR
> GND
> 5
> ↔
> 7
> GND
> DSR
> 6
> ←
> 20
> DTR
> RTS
> 7
> →
> 5
> CTS
> CTS
> 8
> ←
> 4
> RTS
> RI
> 9
> NC
>
>
>
>
> Take one probe of the meter and
put it on pin 4 of the DB9 and the
> other on pin 6 of the DB25. It
should beep or light up (however
> you meter functions to indicate
a connection). Then do the same
> for the DSR line on pin 6 to pin
20. And finally the RTS and CTS
> pins 7->5 and 8-> 4. If they are
crossed in some manner, then you
> will not get a beep or a light.
>
> Hope that makes sense.
>
> Kurt
>
>
> On Tue, Apr 9, 2019, at 7:38 AM,
Thomas Morehouse wrote:
>> Thanks for the comments gents.
Learn something every day.
>>
>> Kurt, on the "crossed wires"
issue, what is the procedure for
>> fixing the problem? I sure don't
want to pull something apart,
>> or buy even *more* adapters!
>>
>> Thanks.
>> Tom M.
>>
>>
>> On Tue, Apr 9, 2019 at 10:03 AM
Kurt McCullum <ku...@fastmail.com
<mailto:ku...@fastmail.com>
>> <mailto:ku...@fastmail.com
<mailto:ku...@fastmail.com>>> wrote:
>>
>>
>> What you are describing happens to
me when the either the
>> CTS/RTS or DTR/DSR wires in your
cable are crossed.
>>
>> Example. The CTS pin listens
(checks for voltage) to the RTS
>> pin on the other end. If you have
a cable where RTS goes
>> straight to RTS and CTS going
straight to CTS, then you have
>> two ends of the cable both feeding
voltage to the same wire.
>> This causes the screen to go dim.
the DTR/DSR pins can
>> produce the same issue.
>>
>> Kurt
>>
>> On Tue, Apr 9, 2019, at 5:33 AM,
Thomas Morehouse wrote:
>>> Now that I've got my usb/serial
link working (M102 to Dell
>>> laptop), I notice the 102's
screen get quite dim when the
>>> cable is in the 102's 25 pin
serial port.
>>>
>>> Doesn't need to be connected to
the Dell. Just when you plug
>>> the usb/serial cable into the
102. Unplug the cable, 102
>>> screen returns to normal
visibility.
>>>
>>> Something to worry about? or
just live with it? I wouldn't
>>> have thought the usb/serial
cable chip would put such a
>>> drain on the system. Happens
with battery power, or even
>>> with external 6 volt poweer.
>>>
>>> Thanks.
>>> Tom M.
>>>
>>
>
