[GreenKeys] Usb adapter
ad7i
ad7i at ad7i.net
Sat Dec 11 11:59:45 EST 2021
Earlier this year I was working with David, W1HKJ, the primary developer of
FLDIGI, to create a FLDIGI software widget (named flio) that would allow
data that appeared in the RX and TX windows of FLDIGI to be sent as ASCII
to a USB serial port. I then had an Arduino like device that would take
the output of the USB-Serial bridge chip and send it to a TTY as 5 unit
Baudot code, so that a TTY could print content decoded by FLDIGI (so QSOs
in modes with significant processing gain, such as Olivia and Domino, could
be copied on a mechanical TTY). And it worked great, except that flow
control didn't work. Although the serial link was operating at 9600 bps,
the actual character rate was the same rate that data appeared in the
FLDIGI window. So for Olivia, the character rate was less than the 6-ish
chars per second of 60 WPM, so no overflows. But I also wanted it to work
with some of the higher speed modes (mostly to test the flow control). In
some cases flow control would work, in other cases it would not.
In case it's of interest to some of those following this thread, I've
pasted below some of my test results.
Paul, ad7i
======================================================
Results of testing USB to serial converters on Debian and Windows
Converters tested:
CH340G - This is the native USB to serial converter on most all clone
Arduino Uno boards (and others).
CP2102 - produced by Silicon Labs. I have several of these as "modules"
where the CP2102 is mounted on a PCB purchased from Ebay for an average of
$2 each.
FTDI - The gold standard in USB to serial conversion, except the ones I'm
using are most likely counterfeit, knock offs. Purchased as "modules"
where the FTDI chip is mounted on a PCB purchased from Ebay for an average
$3 each.
Applications software used:
fldigi with flio (debian linux and Windows 10)
Realterm (windows 10)
Picocom (debian linux)
Receiving Hardware
Arduino Uno with software to function as an ASCII to Baudot converter.
Serial input link speed 9600 8N1 with input flow control of either RTS/CTS
or Xon/Xoff. Serial output is 5 unit Baudot code, TTL and AFSK, operating
at 45.45 baud (60 WPM, approximately one output character every 163 ms)
Test Text
The text message consisted of four lines of "quick brown fox...",
approximately 52 characters per line. Normally this would take
approximately 45 seconds to output from the Arduino as 60 WPM Baudot code
if there was no over-run on the Arduino serial input (i.e., flow control
working normally).
Arduino SW Fifo
The Arduino SW fifo is 50 bytes deep. When 25 characters are in the fifo
the XOFF is transmitted OR CTS is de-asserted (NOT clear to send). When
there are less than 5 characters on the fifo, the XON is transmitted OR CTS
is asserted (clear to send).
TESTING UNDER DEBIAN
General Comments: Operation of flidi and flio under Linux were stable and
well behaved. No issues with either of these programs.
Test cases and results
OS: Debian Linux
Conv: CH340G
Flow: RTS/CTS
App: fldigi flio
Results: Flow Control *FAIL*
OS: Debian Linux
Conv: CH340G
Flow: RTS/CTS
App: picocom
Results: Flow Control *FAIL*
OS: Debian Linux
Conv: CH340G
Flow: Xon-Xoff
App: fldigi flio
Results: Flow Control *FAIL*
OS: Debian Linux
Conv: CH340G
Flow: Xon-Xoff
App: picocom
Results: Flow Control *FAIL*
------
OS: Debian Linux
Conv: CP2102
Flow: RTS/CTS
App: fldigi flio
Results: Flow Control Works
OS: Debian Linux
Conv: CP2102
Flow: RTS/CTS
App: picocom
Results: Flow Control Works
OS: Debian Linux
Conv: CP2102
Flow: Xon-Xoff
App: fldigi flio
Results: Flow Control *FAIL*
OS: Debian Linux
Conv: CP2102
Flow: Xon-Xoff
App: picocom
Results: Flow Control *FAIL*
------
OS: Debian Linux
Conv: FTDI-KO
Flow: RTS/CTS
App: fldigi flio
Results: Flow Control Works
OS: Debian Linux
Conv: FTDI-KO
Flow: RTS/CTS
App: picocom
Results: did not test this case because worked OK with flio
OS: Debian Linux
Conv: FTDI-KO
Flow: Xon-Xoff
App: fldigi flio
Results: Flow Control Works
OS: Debian Linux
Conv: FTDI-KO
Flow: Xon-Xoff
App: picocom
Results: did not test this case because worked OK with flio
TESTING UNDER WINDOWs 10
General Comments: Operation of flidi was stable and well behaved.
Operation of flio was inconsistent and gave odd results, without regard to
the issue of flow control. In some cases text characters in the flio data
window made no sense, as though there was a synchronization problem in the
data transfer between fldigi and flio, or characters were dropped. Also,
in some cases flio would not "see" the Arduino (no green diamond) after
changing the port parameters in flio. Only when flio was closed and
reopened would flio then see the Arduino board.
Test cases and results
OS: Windows 10
Conv: CH340G
Flow: RTS/CTS
App: fldigi flio
Results: Flow Control *FAIL*
OS: Windows 10
Conv: CH340G
Flow: RTS/CTS
App: RealTerm
Results: Flow Control Works
OS: Windows 10
Conv: CH340G
Flow: Xon-Xoff
App: fldigi flio
Results: Flow Control *FAIL*
OS: Windows 10
Conv: CH340G
Flow: Xon-Xoff
App: RealTerm
Results: Flow Control *FAIL*
------
OS: Windows 10
Conv: CP2102
Flow: RTS/CTS
App: fldigi flio
Results: Flow Control *FAIL*
OS: Windows 10
Conv: CP2102
Flow: RTS/CTS
App: RealTerm
Results: Flow Control Works
OS: Windows 10
Conv: CP2102
Flow: Xon-Xoff
App: fldigi flio
Results: Flow Control Works
OS: Windows 10
Conv: CP2102
Flow: Xon-Xoff
App: RealTerm
Results: Flow Control Works
------
OS: Windows 10
Conv: FTDI-KO
Flow: RTS/CTS
App: fldigi flio
Results: Flow Control *FAIL*
OS: Windows 10
Conv: FTDI-KO
Flow: RTS/CTS
App: RealTerm
Results: Flow Control Works
OS: Windows 10
Conv: FTDI-KO
Flow: Xon-Xoff
App: fldigi flio
Results: Flow indeterminate, bad data in flio window
OS: Windows 10
Conv: FTDI-KO
Flow: Xon-Xoff
App: RealTerm
Results: Flow Control Works
---ooOoo-
On Sat, Dec 11, 2021 at 11:39 AM William Wuttke <wcwuttke at gmail.com> wrote:
> The Digi Edgeport 8-port USB to RS-232 works fine at 45 baud 5 bits. They
> are expensive new but can be had for less than $50 on ebay.
>
> Bill
>
> On Fri, Dec 10, 2021 at 7:52 PM Paul Heller <paul0926 at comcast.net> wrote:
>
>> I’ve had little success with these USB to RS-232 adapters at 45 baud. I
>> have tried more than one, including the Sabrent one Michael linked from
>> Amazon (I bought two many years ago and neither worked). Your mileage may
>> vary.
>>
>> The ITTY program transmits at 45 baud and works fine on a Windows
>> computer with a real RS-232 port but not with a Windows computer with a USB
>> port. I suspect Windows USB drivers are somehow getting in the way. The
>> specs for the Sabrent converter on Amazon state Baud rate: 300bps to
>> 1Mbps. Perhaps that is for Windows only.
>>
>> Is anyone able to get slow baud rates using Windows with one of these USB
>> to RS-232 adapters?
>>
>> Paul
>> W2TTY
>>
>> On Dec 10, 2021, at 6:52 PM, Michael Katzmann <vk2bea at gmail.com> wrote:
>>
>>
>> I worked to get the Linux kernel driver to work at arbitrary baud rates
>> on the Prolific PL2303A-TA USB to serial chip.
>>
>> This can do 5 bit / 1.5 stop / 45 baud with the linux driver although the
>> chip can actually get closer to 45.45 Bd if you want to tweak the driver.
>> (the linux ioctl call (termios2 structure) only handles integer bit rates)
>>
>> https://github.com/torvalds/linux/blob/master/drivers/usb/serial/pl2303.c
>>
>> This chip is used in this USB to serial device (and many others)
>> https://www.amazon.com/Sabrent-Converter-Prolific-Chipset-CB-DB9P/dp/B00IDSM6BW
>>
>> I was using it with the ASR33 (110 Bd) but did check the 45 Bd use. As
>> with the 33 you will need to go from RS232 to current loop.
>>
>> Michael NV3Z / VK2BEA / G4NYV
>>
>> On Fri, Dec 10, 2021 at 1:38 PM chris johnson <archangel_cpj at hotmail.com>
>> wrote:
>>
>>> Anyone making a batch of adaptors for usb to model 15 use???? Or have
>>> any already made for sale????
>>> ______________________________________________________________
>>>
>>
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>>
>>
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>> >>> Jordan Spencer Cunningham's GreenKeys Search Tool:
>> https://teletype.net/gksearch
>> >>> 2002-to-present greenkeys archive:
>> http://mailman.qth.net/pipermail/greenkeys/
>> >>> 1998-to-2001 greenkeys archive:
>> http://mailman.qth.net/archive/greenkeys/greenkeys.html
>> >>> Randy Guttery's 2001-to-2009 GreenKeys Search Tool:
>> http://comcents.com/tty/greenkeyssearch.html
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
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>
> ______________________________________________________________
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> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:GreenKeys at mailman.qth.net
>
> >>> Jordan Spencer Cunningham's GreenKeys Search Tool:
> https://teletype.net/gksearch
> >>> 2002-to-present greenkeys archive:
> http://mailman.qth.net/pipermail/greenkeys/
> >>> 1998-to-2001 greenkeys archive:
> http://mailman.qth.net/archive/greenkeys/greenkeys.html
> >>> Randy Guttery's 2001-to-2009 GreenKeys Search Tool:
> http://comcents.com/tty/greenkeyssearch.html
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to ad7i at ad7i.net
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