Re: [M100] Intermittent problem at higher baud rates on RS-232 interface

[Brian K. White]

Oh I misunderstood that. I thought the tnc had that configurable with a 
jumper installed by default.


--
bkw

On 9/27/23 19:37, Jesse Bertier wrote:

I agree that the m100 has unique circuitry contributing to the problem - 
perhaps only 5 volts to work with , perhaps the choice in the resistor values 
chosen on the inputs and outputs, or perhaps when they changed to 330 ohm 
values in that TSB.

Agreed it’s perfectly legit to loop back in this fashion.  What’s odd is other 
older TNCs didn’t do this, at least not by default.  What I didn’t try yet is 
seeing if tickling the DTR output on the m100 changes anything (switching it 
from high to low or vice versa).  That built in telcom program initializes the 
uart and resets the hardware flow control lines, so I would need to write 
something in basic to do the test.

Unfortunately that tnc has traces needing to be cut on the pcb to disable this 
loop back.  They didn’t put jumpers on the loop back options.  Sacrificing one 
of those gender changers was the lazy way to fix it.

Sent from my iPhone


On Sep 27, 2023, at 6:57 PM, Brian K. White  wrote:

On 9/27/23 16:01, Jesse Bertier wrote:

Fellow M100 Enthusiasts:
I kept at it, trying all the various suggestions from the group.  I finally 
solved the issue - the TNC had a loopback connection from DTR to DSR.   The 
problem disappeared entirely when I removed that loopback connection the TNC 
was doing.


It's still curious, because looping back those two lines is perfectly "legal".

It may possibly have a bad effect in some cases simply because of any signal 
being a lie, but electrically it's perfectly legit. And it's not even a data 
problem if neither side is looking at the signal.

I say, this indicates a problem in the 100 (in the design of the circuit, not a 
damage you can repair) not a problem in the radio.

Though the work-around is still fine. I just mean that the conclusion that "aha, the 
radio is the culprit" isn't really the case in my opinion. But even if I think the 
root blame belongs to the 100, I'm not sure there is anything you can do practically to 
fix the 100, and it was simple to make use of an optional configuration in the radio that 
was put there basically just for this reason, to cater to the failings, or more 
generously, quirks of other equipment that might need it.

--
bkw



If interested, I posted the details here:
https://n1ugk.com/2023/09/trs-80-model-100-with-the-kpc-3/ 

With that mystery solved, I can now use the M100 for what I intended to use it 
for.

On Sep 8, 2023, at 7:28 PM, Daryl Tester  
wrote:



On 9/9/23 00:10, Jesse Bertier wrote:



I wanted to follow up with this issue - As it turns out, the TNC itself
seems to be the culprit, at least with the M100.  Even small text strings
get garbled, with software flow control enabled on both sides.  That TNC
works fine with a PC, just not the M100.  Next time I have the scope out,
I’ll take a look at the line and compare, and work back into the M100 as
needed out of curiosity.


Sounds suspiciously like clocking tolerances (of the serial line).  I thought
it used to be 20% (from the "olden days") with 16x oversampling), but current
Internet Wisdom (for what that's worth) says ~ 5%.  If you've got one device
that's slightly fast, and the other slower, you''ll see this sort of behaviour.

(I used to work on a serial port switch in the 80's.  That sod had something 
like
a +0.5% tolerance, although its negative was relatively normal. The above fault
was well known).

Cheers,
  --dt


--
bkw



--
bkw

Re: [M100] Intermittent problem at higher baud rates on RS-232 interface

[Jesse Bertier]

I agree that the m100 has unique circuitry contributing to the problem - 
perhaps only 5 volts to work with , perhaps the choice in the resistor values 
chosen on the inputs and outputs, or perhaps when they changed to 330 ohm 
values in that TSB.  

Agreed it’s perfectly legit to loop back in this fashion.  What’s odd is other 
older TNCs didn’t do this, at least not by default.  What I didn’t try yet is 
seeing if tickling the DTR output on the m100 changes anything (switching it 
from high to low or vice versa).  That built in telcom program initializes the 
uart and resets the hardware flow control lines, so I would need to write 
something in basic to do the test. 

Unfortunately that tnc has traces needing to be cut on the pcb to disable this 
loop back.  They didn’t put jumpers on the loop back options.  Sacrificing one 
of those gender changers was the lazy way to fix it.

Sent from my iPhone

> On Sep 27, 2023, at 6:57 PM, Brian K. White  wrote:
> 
> On 9/27/23 16:01, Jesse Bertier wrote:
>> Fellow M100 Enthusiasts:
>> I kept at it, trying all the various suggestions from the group.  I finally 
>> solved the issue - the TNC had a loopback connection from DTR to DSR.   The 
>> problem disappeared entirely when I removed that loopback connection the TNC 
>> was doing.
> 
> It's still curious, because looping back those two lines is perfectly "legal".
> 
> It may possibly have a bad effect in some cases simply because of any signal 
> being a lie, but electrically it's perfectly legit. And it's not even a data 
> problem if neither side is looking at the signal.
> 
> I say, this indicates a problem in the 100 (in the design of the circuit, not 
> a damage you can repair) not a problem in the radio.
> 
> Though the work-around is still fine. I just mean that the conclusion that 
> "aha, the radio is the culprit" isn't really the case in my opinion. But even 
> if I think the root blame belongs to the 100, I'm not sure there is anything 
> you can do practically to fix the 100, and it was simple to make use of an 
> optional configuration in the radio that was put there basically just for 
> this reason, to cater to the failings, or more generously, quirks of other 
> equipment that might need it.
> 
> --
> bkw
> 
> 
>> If interested, I posted the details here:
>> https://n1ugk.com/2023/09/trs-80-model-100-with-the-kpc-3/ 
>> 
>> With that mystery solved, I can now use the M100 for what I intended to use 
>> it for.
 On Sep 8, 2023, at 7:28 PM, Daryl Tester 
  wrote:
>>> 
 On 9/9/23 00:10, Jesse Bertier wrote:
>>> 
 I wanted to follow up with this issue - As it turns out, the TNC itself
 seems to be the culprit, at least with the M100.  Even small text strings
 get garbled, with software flow control enabled on both sides.  That TNC
 works fine with a PC, just not the M100.  Next time I have the scope out,
 I’ll take a look at the line and compare, and work back into the M100 as
 needed out of curiosity.
>>> 
>>> Sounds suspiciously like clocking tolerances (of the serial line).  I 
>>> thought
>>> it used to be 20% (from the "olden days") with 16x oversampling), but 
>>> current
>>> Internet Wisdom (for what that's worth) says ~ 5%.  If you've got one device
>>> that's slightly fast, and the other slower, you''ll see this sort of 
>>> behaviour.
>>> 
>>> (I used to work on a serial port switch in the 80's.  That sod had 
>>> something like
>>> a +0.5% tolerance, although its negative was relatively normal. The above 
>>> fault
>>> was well known).
>>> 
>>> Cheers,
>>>  --dt
> 
> --
> bkw
> 

Re: [M100] Intermittent problem at higher baud rates on RS-232 interface

[Jesse Bertier]

Hi Alex,Yes, I’ve noticed the lcd dimming on the model 100 sometimes as there was higher current drain or voltage drain from the RS-232 port.I suspect hardware flow control lines is a big contributor to that power drain - anything that pushes the hardware flow control input pins high (I believe they’re pulled down to -5volts within the model 100).  I’m glad it’s now working - and I remember the MFJ model you mention, that was my first TNC .73Sent from my iPhoneOn Sep 27, 2023, at 6:28 PM, Alex ...  wrote:Jesse,I feel like I ran into that exact problem before a couple years ago when I was using my '102 for packet radio. Something also about poor battery life from the laptop while the TNC was plugged in as well? I didn't keep good notes, and I was testing several TNCs (two KPC-3s, a KPC-2, and a MFJ-1274.Thanks for documenting all the detailed measurements and sharing it with the group! -AlexOn Wed, Sep 27, 2023 at 4:08 PM Jesse Bertier  wrote:Fellow M100 Enthusiasts:I kept at it, trying all the various suggestions from the group.  I finally solved the issue - the TNC had a loopback connection from DTR to DSR.   The problem disappeared entirely when I removed that loopback connection the TNC was doing.  If interested, I posted the details here:https://n1ugk.com/2023/09/trs-80-model-100-with-the-kpc-3/With that mystery solved, I can now use the M100 for what I intended to use it for.
On Sep 8, 2023, at 7:28 PM, Daryl Tester  wrote:On 9/9/23 00:10, Jesse Bertier wrote:I wanted to follow up with this issue - As it turns out, the TNC itselfseems to be the culprit, at least with the M100.  Even small text stringsget garbled, with software flow control enabled on both sides.  That TNCworks fine with a PC, just not the M100.  Next time I have the scope out,I’ll take a look at the line and compare, and work back into the M100 asneeded out of curiosity.Sounds suspiciously like clocking tolerances (of the serial line).  I thoughtit used to be 20% (from the "olden days") with 16x oversampling), but currentInternet Wisdom (for what that's worth) says ~ 5%.  If you've got one devicethat's slightly fast, and the other slower, you''ll see this sort of behaviour.(I used to work on a serial port switch in the 80's.  That sod had something likea +0.5% tolerance, although its negative was relatively normal. The above faultwas well known).Cheers,  --dt-- Disclaimer: Any resemblance between the above views and those of my employer, my terminal, or the view out my window are purely coincidental.  Any resemblance between the above and my own views is non-deterministic.  The question of the existence of views in the absence of anyone to hold them is left as an exercise for the reader.The question of the existence of the reader is left as an exercise for the second god coefficient.  (A discussion of non-orthogonal, non-integral polytheism is beyond the scope of this article.) Thanks /usr/games/fortune

Re: [M100] Intermittent problem at higher baud rates on RS-232 interface

[Brian K. White]

On 9/27/23 16:01, Jesse Bertier wrote:

Fellow M100 Enthusiasts:

I kept at it, trying all the various suggestions from the group.  I 
finally solved the issue - the TNC had a loopback connection from DTR to 
DSR.   The problem disappeared entirely when I removed that loopback 
connection the TNC was doing.


It's still curious, because looping back those two lines is perfectly 
"legal".


It may possibly have a bad effect in some cases simply because of any 
signal being a lie, but electrically it's perfectly legit. And it's not 
even a data problem if neither side is looking at the signal.


I say, this indicates a problem in the 100 (in the design of the 
circuit, not a damage you can repair) not a problem in the radio.


Though the work-around is still fine. I just mean that the conclusion 
that "aha, the radio is the culprit" isn't really the case in my 
opinion. But even if I think the root blame belongs to the 100, I'm not 
sure there is anything you can do practically to fix the 100, and it was 
simple to make use of an optional configuration in the radio that was 
put there basically just for this reason, to cater to the failings, or 
more generously, quirks of other equipment that might need it.


--
bkw



If interested, I posted the details here:

https://n1ugk.com/2023/09/trs-80-model-100-with-the-kpc-3/ 



With that mystery solved, I can now use the M100 for what I intended to 
use it for.


On Sep 8, 2023, at 7:28 PM, Daryl Tester 
 wrote:


On 9/9/23 00:10, Jesse Bertier wrote:


I wanted to follow up with this issue - As it turns out, the TNC itself
seems to be the culprit, at least with the M100.  Even small text strings
get garbled, with software flow control enabled on both sides.  That TNC
works fine with a PC, just not the M100.  Next time I have the scope out,
I’ll take a look at the line and compare, and work back into the M100 as
needed out of curiosity.


Sounds suspiciously like clocking tolerances (of the serial line).  I 
thought
it used to be 20% (from the "olden days") with 16x oversampling), but 
current
Internet Wisdom (for what that's worth) says ~ 5%.  If you've got one 
device
that's slightly fast, and the other slower, you''ll see this sort of 
behaviour.


(I used to work on a serial port switch in the 80's.  That sod had 
something like
a +0.5% tolerance, although its negative was relatively normal. The 
above fault

was well known).

Cheers,
 --dt




--
bkw

Re: [M100] Intermittent problem at higher baud rates on RS-232 interface

[Alex ...]

Jesse,
I feel like I ran into that exact problem before a couple years ago when I
was using my '102 for packet radio. Something also about poor battery life
from the laptop while the TNC was plugged in as well? I didn't keep good
notes, and I was testing several TNCs (two KPC-3s, a KPC-2, and a MFJ-1274.

Thanks for documenting all the detailed measurements and sharing it with
the group!
-Alex

On Wed, Sep 27, 2023 at 4:08 PM Jesse Bertier  wrote:

> Fellow M100 Enthusiasts:
>
> I kept at it, trying all the various suggestions from the group.  I
> finally solved the issue - the TNC had a loopback connection from DTR to
> DSR.   The problem disappeared entirely when I removed that loopback
> connection the TNC was doing.
>
> If interested, I posted the details here:
>
> https://n1ugk.com/2023/09/trs-80-model-100-with-the-kpc-3/
>
> With that mystery solved, I can now use the M100 for what I intended to
> use it for.
>
> On Sep 8, 2023, at 7:28 PM, Daryl Tester <
> dt-m...@handcraftedcomputers.com.au> wrote:
>
> On 9/9/23 00:10, Jesse Bertier wrote:
>
> I wanted to follow up with this issue - As it turns out, the TNC itself
> seems to be the culprit, at least with the M100.  Even small text strings
> get garbled, with software flow control enabled on both sides.  That TNC
> works fine with a PC, just not the M100.  Next time I have the scope out,
> I’ll take a look at the line and compare, and work back into the M100 as
> needed out of curiosity.
>
>
> Sounds suspiciously like clocking tolerances (of the serial line).  I
> thought
> it used to be 20% (from the "olden days") with 16x oversampling), but
> current
> Internet Wisdom (for what that's worth) says ~ 5%.  If you've got one
> device
> that's slightly fast, and the other slower, you''ll see this sort of
> behaviour.
>
> (I used to work on a serial port switch in the 80's.  That sod had
> something like
> a +0.5% tolerance, although its negative was relatively normal. The above
> fault
> was well known).
>
> Cheers,
>  --dt
>
>
>

-- 
Disclaimer: Any resemblance between the above views and those of my
employer, my terminal, or the view out my window are purely coincidental.
Any resemblance between the above and my own views is non-deterministic.
The question of the existence of views in the absence of anyone to hold
them is left as an exercise for the reader.
The question of the existence of the reader is left as an exercise for the
second god coefficient.  (A discussion of non-orthogonal, non-integral
polytheism is beyond the scope of this article.) Thanks /usr/games/fortune

Re: [M100] Intermittent problem at higher baud rates on RS-232 interface

[Jesse Bertier]

Fellow M100 Enthusiasts:

I kept at it, trying all the various suggestions from the group.  I finally 
solved the issue - the TNC had a loopback connection from DTR to DSR.   The 
problem disappeared entirely when I removed that loopback connection the TNC 
was doing.  

If interested, I posted the details here:

https://n1ugk.com/2023/09/trs-80-model-100-with-the-kpc-3/

With that mystery solved, I can now use the M100 for what I intended to use it 
for.

> On Sep 8, 2023, at 7:28 PM, Daryl Tester 
>  wrote:
> 
> On 9/9/23 00:10, Jesse Bertier wrote:
> 
>> I wanted to follow up with this issue - As it turns out, the TNC itself
>> seems to be the culprit, at least with the M100.  Even small text strings
>> get garbled, with software flow control enabled on both sides.  That TNC
>> works fine with a PC, just not the M100.  Next time I have the scope out,
>> I’ll take a look at the line and compare, and work back into the M100 as
>> needed out of curiosity.
> 
> Sounds suspiciously like clocking tolerances (of the serial line).  I thought
> it used to be 20% (from the "olden days") with 16x oversampling), but current
> Internet Wisdom (for what that's worth) says ~ 5%.  If you've got one device
> that's slightly fast, and the other slower, you''ll see this sort of 
> behaviour.
> 
> (I used to work on a serial port switch in the 80's.  That sod had something 
> like
> a +0.5% tolerance, although its negative was relatively normal. The above 
> fault
> was well known).
> 
> Cheers,
>  --dt

Re: [M100] Intermittent problem at higher baud rates on RS-232 interface

[Daryl Tester]

On 9/9/23 00:10, Jesse Bertier wrote:


I wanted to follow up with this issue - As it turns out, the TNC itself
seems to be the culprit, at least with the M100.  Even small text strings
get garbled, with software flow control enabled on both sides.  That TNC
works fine with a PC, just not the M100.  Next time I have the scope out,
I’ll take a look at the line and compare, and work back into the M100 as
needed out of curiosity.


Sounds suspiciously like clocking tolerances (of the serial line).  I thought
it used to be 20% (from the "olden days") with 16x oversampling), but current
Internet Wisdom (for what that's worth) says ~ 5%.  If you've got one device
that's slightly fast, and the other slower, you''ll see this sort of behaviour.

(I used to work on a serial port switch in the 80's.  That sod had something 
like
a +0.5% tolerance, although its negative was relatively normal. The above fault
was well known).

Cheers,
  --dt

Re: [M100] Intermittent problem at higher baud rates on RS-232 interface

[Jesse Bertier]

I wanted to follow up with this issue - As it turns out, the TNC itself seems 
to be the culprit, at least with the M100.  Even small text strings get 
garbled, with software flow control enabled on both sides.  That TNC works fine 
with a PC, just not the M100.  Next time I have the scope out, I’ll take a look 
at the line and compare, and work back into the M100 as needed out of curiosity.

Another TNC I recently acquired works just fine at 9600 baud.  The backpack 
drive also works without an issue on this M100.  All is well.

> On Jul 19, 2023, at 8:14 PM, John R. Hogerhuis  wrote:
> 
> Yes. Since the data is processed at the hardware level that makes sense. The 
> garbling I usually see is because of the software level getting behind and 
> dropping portions of multibyte characters (UTF-8) or unprocessed escape 
> sequences (ANSI escapes, x terminal stuff)
> 
> But that may be specific to my use cases of Linux peers. 
> 
> If you're doing 7 bit ASCII then it makes sense to just get whole character 
> sequences dropping out versus intermingled control characters and spurious 
> extended characters. 
> 
> -- John. 

Re: [M100] Intermittent problem at higher baud rates on RS-232 interface

[John R. Hogerhuis]

Yes. Since the data is processed at the hardware level that makes sense.
The garbling I usually see is because of the software level getting behind
and dropping portions of multibyte characters (UTF-8) or unprocessed escape
sequences (ANSI escapes, x terminal stuff)

But that may be specific to my use cases of Linux peers.

If you're doing 7 bit ASCII then it makes sense to just get whole character
sequences dropping out versus intermingled control characters and spurious
extended characters.

-- John.

Re: [M100] Intermittent problem at higher baud rates on RS-232 interface

[Jesse Bertier]

Thanks John, my next test(s) will be transferring programs to/from the M100, 
and I believe I read somewhere that zmodem would work well.  It’s been decades 
since I’ve used it, reminds me of BBSes, and that DOS terminal program, 
TERMINATE (I believe that’s what it was back in the day).

> On Jul 11, 2023, at 5:55 PM, John R. Hogerhuis  wrote:
> 
> " TPDD uses 9600 and 19200 reliably only because it operates in small packets 
> and no screen updates."
> 
> TPDD drives and emulator file services work with no flow control at high 
> speeds because of the half duplex, request/response nature of the TPDD 
> protocol... it's client driven, and the client is either requesting or 
> focused solely on receiving the response to the last request. The server 
> never sends more than about 128 bytes, and never unbidden.
> 
> Since the client is driving (as opposed to the server which could easily 
> blast the 100 with an entire file in some other protocol), the responses are 
> small and the client isn't really doing anything else while receiving the 
> response. It will never be overrun.
> 
> Of course that's very inefficient. Only one half of a two way channel is ever 
> in use. And it's constantly starting and stopping.
> 
> Consider a protocol like zmodem... the peer can adapt to a fast receiver and 
> stream an entire file as one packet.
> 
> -- John.

Re: [M100] Intermittent problem at higher baud rates on RS-232 interface

[Jesse Bertier]

For sure, flow control is key also.  I noticed that the TNC was a mismatch with 
this Model 100, as my PC and other rig have no issues, no garbled characters, 
same baud rate — if I hit it hard with a large chunk of text, the M100 drops 
some chars, but it does not get garbled (odd ASCII chars).  So, time to dig out 
the scope and probe around to visualize that mismatch between the TNC and the 
M100.  

I’m glad to hear others use the M100 with TNCs etc.  

73, N1UGK

> On Jul 10, 2023, at 7:02 AM, Brian Brindle  wrote:
> 
> Hey Jesse - congrats on getting the model T! They make great packet stations 
> for sure. The issue you are describing sounds like a flow control one. 
> Depending on what TNC you are using you should be able to activate XON/XOFF. 
> On my old Timewave I think the command is XFLOW ON. 
> 
> Then just ensure that you have flow control enabled in TERM with STAT 88N1D 
> (For 9600 bps) and you should be good to go. 
> 
> Great to see other amateurs on the list and I know you are going to love the 
> M100 as a tool. My club used them and the LOGBA program for field day this 
> year and it worked out fantastic. Can't beat that screen and battery life. 
> 
> 73 - DE KW4KB
> 
> Brian
>  
> 
> On Sun, Jul 9, 2023 at 6:20 PM Jesse Bertier  > wrote:
>> First time getting my hands on a model T.  I am attempting to connect to a 
>> TNC at 9600 baud.  I have both matched for 8,N,1 and 9600 baud.  TNC works 
>> with other PCs.  I’m using TELCOM and set the parameters correctly.  What 
>> happens at 9600 baud is the text coming into the m100 is garbled mostly and 
>> on occasion some valid words come across.  When I set both to 300 baud, 
>> works perfectly.   It seems to be problematic if there’s a solid block of 
>> text coming in, like a string of 20-30 words for example.  
>> 
>> Before I dig into the problem with the service manual and get out the scope, 
>> does anyone know if these are supposed to work well at 9600 or up to 19,200 
>> ?  Or, does the buffer or machine get overloaded at higher rates?  Is TELCOM 
>> the issue? 
>> 
>> Sent from my iPhone

Re: [M100] Intermittent problem at higher baud rates on RS-232 interface

[Jesse Bertier]

Yes, that video was very helpful, even more helpful was your parts list.  All 
but 2 caps were currently available, and the remaining two had suitable 
equivalents.  I actually improved my technique and experience removing those 
leaky caps.

I tested the TNC again, 9600 baud after the recap, and no difference.  However, 
the good news is another radio I have, same baud rate, works flawlessly.  Same 
with the PC.  My thought is impedance or levels are the issue with that TNC.  
I’ll probe with the scope when connected to that TNC, from the serial line back 
through the UART to see where it’s getting lost.  

Anyhow, the recap needed to be done regardless of my flawed serial port 
“experiment”, so I’m glad thats out of the way.

This is a great resource as well as your videos, and thanks to all who offered 
some tips and advice, it is greatly appreciated.

> On Jul 10, 2023, at 4:45 PM, bir...@soigeneris.com wrote:
> 
> Yes, the M100 caps always need to be replaced. The RS232 output puts a 
> significant load on the -5V which makes for flaky LCD and RS232 operation. If 
> there are any traces under/around the caps that look dark they need to be 
> mechanically cleaned and neutralized (if corrosion was bad) to stave off 
> further corrosion. I have done a few videos on M100 recapping describing the 
> process. 
> 
> Jeff
>  
> From: M100  <mailto:m100-boun...@lists.bitchin100.com>> On Behalf Of Jesse Bertier
> Sent: Monday, July 10, 2023 12:57 PM
> To: m...@bitchin100.com <mailto:m...@bitchin100.com>
> Subject: Re: [M100] Intermittent problem at higher baud rates on RS-232 
> interface
>  
> Hi Jeff,
>  
> Thank you - I noted my serial # was after the 30601 mark, and verified 
> the 330 ohm resistors are in fact on my board.  I then took a closer look 
> over the board and noticed just about every electrolytic cap leaked.  The 
> flipflop near the power supply area was also warm, so I powered it off and 
> may order some caps.  I’m thinking at this point a recap before digging into 
> the RS-232 port any further would be a good place to start.  
>  
> This is a fantastic group, thank you all for the replies!
> 
> 
>> On Jul 9, 2023, at 7:12 PM, > <mailto:bir...@soigeneris.com>> > <mailto:bir...@soigeneris.com>> wrote:
>>  
>> The TPDD1, TPDD2, Backpack, etc. use 19200 successfully. If you can adjust 
>> the intercharacter delay on the TNC is might help. Also note that some early 
>> M100s had the wrong resistors in the output lines for the RS232 port. They 
>> fitted 5.6K from factory but they quickly revised that down to 330ohm as 
>> some devise would not work with it. 
>> 
>> I did a video on the factory mod a while back. A link to the technical 
>> bulletin is in the video description:
>> 
>> https://youtu.be/KPFnwv_nDD8
>>  
>> Jeff Birt
>>  
>> From: M100 > <mailto:m100-boun...@lists.bitchin100.com>> On Behalf Of Gregory McGill
>> Sent: Sunday, July 9, 2023 5:40 PM
>> To: m...@bitchin100.com <mailto:m...@bitchin100.com>
>> Subject: Re: [M100] Intermittent problem at higher baud rates on RS-232 
>> interface
>>  
>> there's no hardware flow control on the 100 with telcom
>> use a better terminal and hardware flow control at any baud rate over 2400 
>>  
>>  
>> On Sun, Jul 9, 2023 at 3:19 PM Jesse Bertier > <mailto:berti...@gmail.com>> wrote:
>>> First time getting my hands on a model T.  I am attempting to connect to a 
>>> TNC at 9600 baud.  I have both matched for 8,N,1 and 9600 baud.  TNC works 
>>> with other PCs.  I’m using TELCOM and set the parameters correctly.  What 
>>> happens at 9600 baud is the text coming into the m100 is garbled mostly and 
>>> on occasion some valid words come across.  When I set both to 300 baud, 
>>> works perfectly.   It seems to be problematic if there’s a solid block of 
>>> text coming in, like a string of 20-30 words for example.  
>>> 
>>> Before I dig into the problem with the service manual and get out the 
>>> scope, does anyone know if these are supposed to work well at 9600 or up to 
>>> 19,200 ?  Or, does the buffer or machine get overloaded at higher rates?  
>>> Is TELCOM the issue? 
>>> 
>>> Sent from my iPhone

Re: [M100] Intermittent problem at higher baud rates on RS-232 interface

[John R. Hogerhuis]

" TPDD uses 9600 and 19200 reliably only because it operates in small
packets and no screen updates."

TPDD drives and emulator file services work with no flow control at high
speeds because of the half duplex, request/response nature of the TPDD
protocol... it's client driven, and the client is either requesting or
focused solely on receiving the response to the last request. The server
never sends more than about 128 bytes, and never unbidden.

Since the client is driving (as opposed to the server which could easily
blast the 100 with an entire file in some other protocol), the responses
are small and the client isn't really doing anything else while receiving
the response. It will never be overrun.

Of course that's very inefficient. Only one half of a two way channel is
ever in use. And it's constantly starting and stopping.

Consider a protocol like zmodem... the peer can adapt to a fast receiver
and stream an entire file as one packet.

-- John.

>

Re: [M100] Intermittent problem at higher baud rates on RS-232 interface

[Brian White]

The receive buffer on m100 is small and tge screen updates in telcom take
so much time that, even with xon/off enabled, you can't go over 600 baud
reliably. The in-band software flow control has a minimum round trip time
that means that by the time the 100 sends the "stop sending" and the other
side gets it and stops, there are too many bytes already in flight and it
overflows the 100s receive buffer. It can keep up with 600, 1200 it almost
manages but not quite.

With the screen updates turned off you can go higher but 9600 may still be
too high. It depends on the software being used on the 100 and the size of
any continuous transmissions.

TPDD uses 9600 and 19200 reliably only because it operates in small packets
and no screen updates. TPDD clients have small fast machine language
routines to process the bytes in as few cpu cycles as possible, with no
screen updates in the inner loop, and the largest possible packet in the
protocol is still under 256 bytes. So even with no flow control, the
protocol itself stops transmission anyway and waits for an ack before
sending the next packet.

You may be able to use 9600 for tnc but only if the software is not also
drawing on the screen at the same time it's receiving, and especially if it
naturally operates in small chunks with breaks.

Using TELCOM, with the screen enabled, and possibly arbitrarily long
continuous downloads, you're limited to 600 baud.

The machine physically has rts/cts hardware, but nothing in the system rom
(including telcom) enables rts/cts. The only software known to use rts/cts
is HTERM and I think TBACK, which you can find on bitchen100.
That can reliably go over 600 because it has it's own machine language code
to operate the uart. Anything else will be limited to xon/xoff.


bkw

On Sun, Jul 9, 2023, 6:20 PM Jesse Bertier  wrote:

> First time getting my hands on a model T.  I am attempting to connect to a
> TNC at 9600 baud.  I have both matched for 8,N,1 and 9600 baud.  TNC works
> with other PCs.  I’m using TELCOM and set the parameters correctly.  What
> happens at 9600 baud is the text coming into the m100 is garbled mostly and
> on occasion some valid words come across.  When I set both to 300 baud,
> works perfectly.   It seems to be problematic if there’s a solid block of
> text coming in, like a string of 20-30 words for example.
>
> Before I dig into the problem with the service manual and get out the
> scope, does anyone know if these are supposed to work well at 9600 or up to
> 19,200 ?  Or, does the buffer or machine get overloaded at higher rates?
> Is TELCOM the issue?
>
> Sent from my iPhone

Re: [M100] Intermittent problem at higher baud rates on RS-232 interface

[birt_j]

Yes, the M100 caps always need to be replaced. The RS232 output puts a 
significant load on the -5V which makes for flaky LCD and RS232 operation. If 
there are any traces under/around the caps that look dark they need to be 
mechanically cleaned and neutralized (if corrosion was bad) to stave off 
further corrosion. I have done a few videos on M100 recapping describing the 
process. 

Jeff

 

From: M100  On Behalf Of Jesse Bertier
Sent: Monday, July 10, 2023 12:57 PM
To: m...@bitchin100.com
Subject: Re: [M100] Intermittent problem at higher baud rates on RS-232 
interface

 

Hi Jeff,

 

Thank you - I noted my serial # was after the 30601 mark, and verified the 
330 ohm resistors are in fact on my board.  I then took a closer look over the 
board and noticed just about every electrolytic cap leaked.  The flipflop near 
the power supply area was also warm, so I powered it off and may order some 
caps.  I’m thinking at this point a recap before digging into the RS-232 port 
any further would be a good place to start.  

 

This is a fantastic group, thank you all for the replies!





On Jul 9, 2023, at 7:12 PM, mailto:bir...@soigeneris.com> > mailto:bir...@soigeneris.com> > wrote:

 

The TPDD1, TPDD2, Backpack, etc. use 19200 successfully. If you can adjust the 
intercharacter delay on the TNC is might help. Also note that some early M100s 
had the wrong resistors in the output lines for the RS232 port. They fitted 
5.6K from factory but they quickly revised that down to 330ohm as some devise 
would not work with it. 

I did a video on the factory mod a while back. A link to the technical bulletin 
is in the video description:

https://youtu.be/KPFnwv_nDD8

 

Jeff Birt

 

From: M100 mailto:m100-boun...@lists.bitchin100.com> > On Behalf Of Gregory McGill
Sent: Sunday, July 9, 2023 5:40 PM
To: m...@bitchin100.com <mailto:m...@bitchin100.com> 
Subject: Re: [M100] Intermittent problem at higher baud rates on RS-232 
interface

 

there's no hardware flow control on the 100 with telcom

use a better terminal and hardware flow control at any baud rate over 2400 

 

 

On Sun, Jul 9, 2023 at 3:19 PM Jesse Bertier mailto:berti...@gmail.com> > wrote:

First time getting my hands on a model T.  I am attempting to connect to a TNC 
at 9600 baud.  I have both matched for 8,N,1 and 9600 baud.  TNC works with 
other PCs.  I’m using TELCOM and set the parameters correctly.  What happens at 
9600 baud is the text coming into the m100 is garbled mostly and on occasion 
some valid words come across.  When I set both to 300 baud, works perfectly.   
It seems to be problematic if there’s a solid block of text coming in, like a 
string of 20-30 words for example.  

Before I dig into the problem with the service manual and get out the scope, 
does anyone know if these are supposed to work well at 9600 or up to 19,200 ?  
Or, does the buffer or machine get overloaded at higher rates?  Is TELCOM the 
issue? 

Sent from my iPhone

 

Re: [M100] Intermittent problem at higher baud rates on RS-232 interface

[Gregory McGill]

i have cap kits in my store arcadeshopper.com

On Mon, Jul 10, 2023 at 10:58 AM Jesse Bertier  wrote:

> Hi Jeff,
>
> Thank you - I noted my serial # was after the 30601 mark, and verified
> the 330 ohm resistors are in fact on my board.  I then took a closer look
> over the board and noticed just about every electrolytic cap leaked.  The
> flipflop near the power supply area was also warm, so I powered it off and
> may order some caps.  I’m thinking at this point a recap before digging
> into the RS-232 port any further would be a good place to start.
>
> This is a fantastic group, thank you all for the replies!
>
> On Jul 9, 2023, at 7:12 PM,  
> wrote:
>
> The TPDD1, TPDD2, Backpack, etc. use 19200 successfully. If you can adjust
> the intercharacter delay on the TNC is might help. Also note that some
> early M100s had the wrong resistors in the output lines for the RS232 port.
> They fitted 5.6K from factory but they quickly revised that down to 330ohm
> as some devise would not work with it.
>
> I did a video on the factory mod a while back. A link to the technical
> bulletin is in the video description:
>
> https://youtu.be/KPFnwv_nDD8
>
> Jeff Birt
>
> *From:* M100  *On Behalf Of *Gregory
> McGill
> *Sent:* Sunday, July 9, 2023 5:40 PM
> *To:* m...@bitchin100.com
> *Subject:* Re: [M100] Intermittent problem at higher baud rates on RS-232
> interface
>
> there's no hardware flow control on the 100 with telcom
> use a better terminal and hardware flow control at any baud rate over 2400
>
>
> On Sun, Jul 9, 2023 at 3:19 PM Jesse Bertier  wrote:
>
> First time getting my hands on a model T.  I am attempting to connect to a
> TNC at 9600 baud.  I have both matched for 8,N,1 and 9600 baud.  TNC works
> with other PCs.  I’m using TELCOM and set the parameters correctly.  What
> happens at 9600 baud is the text coming into the m100 is garbled mostly and
> on occasion some valid words come across.  When I set both to 300 baud,
> works perfectly.   It seems to be problematic if there’s a solid block of
> text coming in, like a string of 20-30 words for example.
>
> Before I dig into the problem with the service manual and get out the
> scope, does anyone know if these are supposed to work well at 9600 or up to
> 19,200 ?  Or, does the buffer or machine get overloaded at higher rates?
> Is TELCOM the issue?
>
> Sent from my iPhone
>
>
>

Re: [M100] Intermittent problem at higher baud rates on RS-232 interface

[Peter Vollan]

stat 98n1,e

On Sun, 9 Jul 2023 at 15:40, Gregory McGill  wrote:

> there's no hardware flow control on the 100 with telcom
> use a better terminal and hardware flow control at any baud rate over 2400
>
>
> On Sun, Jul 9, 2023 at 3:19 PM Jesse Bertier  wrote:
>
>> First time getting my hands on a model T.  I am attempting to connect to
>> a TNC at 9600 baud.  I have both matched for 8,N,1 and 9600 baud.  TNC
>> works with other PCs.  I’m using TELCOM and set the parameters correctly.
>> What happens at 9600 baud is the text coming into the m100 is garbled
>> mostly and on occasion some valid words come across.  When I set both to
>> 300 baud, works perfectly.   It seems to be problematic if there’s a solid
>> block of text coming in, like a string of 20-30 words for example.
>>
>> Before I dig into the problem with the service manual and get out the
>> scope, does anyone know if these are supposed to work well at 9600 or up to
>> 19,200 ?  Or, does the buffer or machine get overloaded at higher rates?
>> Is TELCOM the issue?
>>
>> Sent from my iPhone
>
>

Re: [M100] Intermittent problem at higher baud rates on RS-232 interface

[Peter Vollan]

What about software flow control?

On Sun, 9 Jul 2023 at 15:40, Gregory McGill  wrote:

> there's no hardware flow control on the 100 with telcom
> use a better terminal and hardware flow control at any baud rate over 2400
>
>
> On Sun, Jul 9, 2023 at 3:19 PM Jesse Bertier  wrote:
>
>> First time getting my hands on a model T.  I am attempting to connect to
>> a TNC at 9600 baud.  I have both matched for 8,N,1 and 9600 baud.  TNC
>> works with other PCs.  I’m using TELCOM and set the parameters correctly.
>> What happens at 9600 baud is the text coming into the m100 is garbled
>> mostly and on occasion some valid words come across.  When I set both to
>> 300 baud, works perfectly.   It seems to be problematic if there’s a solid
>> block of text coming in, like a string of 20-30 words for example.
>>
>> Before I dig into the problem with the service manual and get out the
>> scope, does anyone know if these are supposed to work well at 9600 or up to
>> 19,200 ?  Or, does the buffer or machine get overloaded at higher rates?
>> Is TELCOM the issue?
>>
>> Sent from my iPhone
>
>

Re: [M100] Intermittent problem at higher baud rates on RS-232 interface

[Jesse Bertier]

Hi Jeff,

Thank you - I noted my serial # was after the 30601 mark, and verified the 
330 ohm resistors are in fact on my board.  I then took a closer look over the 
board and noticed just about every electrolytic cap leaked.  The flipflop near 
the power supply area was also warm, so I powered it off and may order some 
caps.  I’m thinking at this point a recap before digging into the RS-232 port 
any further would be a good place to start.  

This is a fantastic group, thank you all for the replies!

> On Jul 9, 2023, at 7:12 PM,   
> wrote:
> 
> The TPDD1, TPDD2, Backpack, etc. use 19200 successfully. If you can adjust 
> the intercharacter delay on the TNC is might help. Also note that some early 
> M100s had the wrong resistors in the output lines for the RS232 port. They 
> fitted 5.6K from factory but they quickly revised that down to 330ohm as some 
> devise would not work with it. 
> 
> I did a video on the factory mod a while back. A link to the technical 
> bulletin is in the video description:
> 
> https://youtu.be/KPFnwv_nDD8
>  
> Jeff Birt
>  
> From: M100  <mailto:m100-boun...@lists.bitchin100.com>> On Behalf Of Gregory McGill
> Sent: Sunday, July 9, 2023 5:40 PM
> To: m...@bitchin100.com <mailto:m...@bitchin100.com>
> Subject: Re: [M100] Intermittent problem at higher baud rates on RS-232 
> interface
>  
> there's no hardware flow control on the 100 with telcom
> use a better terminal and hardware flow control at any baud rate over 2400 
>  
>  
> On Sun, Jul 9, 2023 at 3:19 PM Jesse Bertier  <mailto:berti...@gmail.com>> wrote:
>> First time getting my hands on a model T.  I am attempting to connect to a 
>> TNC at 9600 baud.  I have both matched for 8,N,1 and 9600 baud.  TNC works 
>> with other PCs.  I’m using TELCOM and set the parameters correctly.  What 
>> happens at 9600 baud is the text coming into the m100 is garbled mostly and 
>> on occasion some valid words come across.  When I set both to 300 baud, 
>> works perfectly.   It seems to be problematic if there’s a solid block of 
>> text coming in, like a string of 20-30 words for example.  
>> 
>> Before I dig into the problem with the service manual and get out the scope, 
>> does anyone know if these are supposed to work well at 9600 or up to 19,200 
>> ?  Or, does the buffer or machine get overloaded at higher rates?  Is TELCOM 
>> the issue? 
>> 
>> Sent from my iPhone

Re: [M100] Intermittent problem at higher baud rates on RS-232 interface

[Brian Brindle]

And of course I didn't see my mistake until seconds after hitting send..
The settings to enable flow control are STAT 88N1E - sorry about that.



On Mon, Jul 10, 2023 at 7:02 AM Brian Brindle  wrote:

> Hey Jesse - congrats on getting the model T! They make great packet
> stations for sure. The issue you are describing sounds like a flow control
> one. Depending on what TNC you are using you should be able to activate
> XON/XOFF. On my old Timewave I think the command is XFLOW ON.
>
> Then just ensure that you have flow control enabled in TERM with STAT
> 88N1D (For 9600 bps) and you should be good to go.
>
> Great to see other amateurs on the list and I know you are going to love
> the M100 as a tool. My club used them and the LOGBA program for field day
> this year and it worked out fantastic. Can't beat that screen and battery
> life.
>
> 73 - DE KW4KB
>
> Brian
>
>
> On Sun, Jul 9, 2023 at 6:20 PM Jesse Bertier  wrote:
>
>> First time getting my hands on a model T.  I am attempting to connect to
>> a TNC at 9600 baud.  I have both matched for 8,N,1 and 9600 baud.  TNC
>> works with other PCs.  I’m using TELCOM and set the parameters correctly.
>> What happens at 9600 baud is the text coming into the m100 is garbled
>> mostly and on occasion some valid words come across.  When I set both to
>> 300 baud, works perfectly.   It seems to be problematic if there’s a solid
>> block of text coming in, like a string of 20-30 words for example.
>>
>> Before I dig into the problem with the service manual and get out the
>> scope, does anyone know if these are supposed to work well at 9600 or up to
>> 19,200 ?  Or, does the buffer or machine get overloaded at higher rates?
>> Is TELCOM the issue?
>>
>> Sent from my iPhone
>
>

Re: [M100] Intermittent problem at higher baud rates on RS-232 interface

[Brian Brindle]

Hey Jesse - congrats on getting the model T! They make great packet
stations for sure. The issue you are describing sounds like a flow control
one. Depending on what TNC you are using you should be able to activate
XON/XOFF. On my old Timewave I think the command is XFLOW ON.

Then just ensure that you have flow control enabled in TERM with STAT 88N1D
(For 9600 bps) and you should be good to go.

Great to see other amateurs on the list and I know you are going to love
the M100 as a tool. My club used them and the LOGBA program for field day
this year and it worked out fantastic. Can't beat that screen and battery
life.

73 - DE KW4KB

Brian


On Sun, Jul 9, 2023 at 6:20 PM Jesse Bertier  wrote:

> First time getting my hands on a model T.  I am attempting to connect to a
> TNC at 9600 baud.  I have both matched for 8,N,1 and 9600 baud.  TNC works
> with other PCs.  I’m using TELCOM and set the parameters correctly.  What
> happens at 9600 baud is the text coming into the m100 is garbled mostly and
> on occasion some valid words come across.  When I set both to 300 baud,
> works perfectly.   It seems to be problematic if there’s a solid block of
> text coming in, like a string of 20-30 words for example.
>
> Before I dig into the problem with the service manual and get out the
> scope, does anyone know if these are supposed to work well at 9600 or up to
> 19,200 ?  Or, does the buffer or machine get overloaded at higher rates?
> Is TELCOM the issue?
>
> Sent from my iPhone

Re: [M100] Intermittent problem at higher baud rates on RS-232 interface

[John R. Hogerhuis]

Probably peer is overrunning m100's receive buffer.

-- John.

On Sun, Jul 9, 2023, 3:20 PM Jesse Bertier  wrote:

> First time getting my hands on a model T.  I am attempting to connect to a
> TNC at 9600 baud.  I have both matched for 8,N,1 and 9600 baud.  TNC works
> with other PCs.  I’m using TELCOM and set the parameters correctly.  What
> happens at 9600 baud is the text coming into the m100 is garbled mostly and
> on occasion some valid words come across.  When I set both to 300 baud,
> works perfectly.   It seems to be problematic if there’s a solid block of
> text coming in, like a string of 20-30 words for example.
>
> Before I dig into the problem with the service manual and get out the
> scope, does anyone know if these are supposed to work well at 9600 or up to
> 19,200 ?  Or, does the buffer or machine get overloaded at higher rates?
> Is TELCOM the issue?
>
> Sent from my iPhone

Re: [M100] Intermittent problem at higher baud rates on RS-232 interface

[birt_j]

The TPDD1, TPDD2, Backpack, etc. use 19200 successfully. If you can adjust the 
intercharacter delay on the TNC is might help. Also note that some early M100s 
had the wrong resistors in the output lines for the RS232 port. They fitted 
5.6K from factory but they quickly revised that down to 330ohm as some devise 
would not work with it. 

I did a video on the factory mod a while back. A link to the technical bulletin 
is in the video description:

https://youtu.be/KPFnwv_nDD8

 

Jeff Birt

 

From: M100  On Behalf Of Gregory McGill
Sent: Sunday, July 9, 2023 5:40 PM
To: m...@bitchin100.com
Subject: Re: [M100] Intermittent problem at higher baud rates on RS-232 
interface

 

there's no hardware flow control on the 100 with telcom

use a better terminal and hardware flow control at any baud rate over 2400 

 

 

On Sun, Jul 9, 2023 at 3:19 PM Jesse Bertier mailto:berti...@gmail.com> > wrote:

First time getting my hands on a model T.  I am attempting to connect to a TNC 
at 9600 baud.  I have both matched for 8,N,1 and 9600 baud.  TNC works with 
other PCs.  I’m using TELCOM and set the parameters correctly.  What happens at 
9600 baud is the text coming into the m100 is garbled mostly and on occasion 
some valid words come across.  When I set both to 300 baud, works perfectly.   
It seems to be problematic if there’s a solid block of text coming in, like a 
string of 20-30 words for example.  

Before I dig into the problem with the service manual and get out the scope, 
does anyone know if these are supposed to work well at 9600 or up to 19,200 ?  
Or, does the buffer or machine get overloaded at higher rates?  Is TELCOM the 
issue? 

Sent from my iPhone

Re: [M100] Intermittent problem at higher baud rates on RS-232 interface

[Gregory McGill]

there's no hardware flow control on the 100 with telcom
use a better terminal and hardware flow control at any baud rate over 2400


On Sun, Jul 9, 2023 at 3:19 PM Jesse Bertier  wrote:

> First time getting my hands on a model T.  I am attempting to connect to a
> TNC at 9600 baud.  I have both matched for 8,N,1 and 9600 baud.  TNC works
> with other PCs.  I’m using TELCOM and set the parameters correctly.  What
> happens at 9600 baud is the text coming into the m100 is garbled mostly and
> on occasion some valid words come across.  When I set both to 300 baud,
> works perfectly.   It seems to be problematic if there’s a solid block of
> text coming in, like a string of 20-30 words for example.
>
> Before I dig into the problem with the service manual and get out the
> scope, does anyone know if these are supposed to work well at 9600 or up to
> 19,200 ?  Or, does the buffer or machine get overloaded at higher rates?
> Is TELCOM the issue?
>
> Sent from my iPhone