Try loopback on your usb-serial adapter.  That is, connect pin 2 and
pin 3 (tx and rx, or vice versa).  Then run something like:

  screen /dev/ttyUSB0 115200

and type some letters on the keyboard and see if they echo back at
you.  If so, the serial cable is working.  If not, you might need a
different serial cable.

You can kill off the screen session with Ctrl-A k, or just yank the
usb connector and screen will helpfully exit.

Another thought, you might need to fix the permissions.  Often the
usb-serial device file will be created owned by the dialout group.

  ls -al /dev/ttyUSB*

If your user isn't in the dialout group, then you might not be able to
open it.  Trying it as root will test that theory.  To fix the group
ownership in the future, try adding your user name to the dialout
group in /etc/group.  You will need to log out and then back in before
the change will take effect (unless there is a shortcut I don't know
about).


Russell

On Sat, Dec 9, 2017 at 4:34 PM, Denis Heidtmann
<[email protected]> wrote:
> Some progress.  I executed "sigrok-cli --driver
> mastech-mas345:conn=/dev/ttyUSB0 --samples 10" forgetting that the meter
> was not plugged into the adapter--got "sr: serial: Didn't find a valid
> packet (read 0 bytes).
> No devices found."  Plugged in the meter, then got no response, but exactly
> 10 seconds delay 'till the prompt returned.  And the default data rate is
> 1/sec.  So it seems something was listening for the 10 samples.  But if the
> samples were acquired I do not know where they went.  I was expecting they
> would appear in the terminal.
>
> Clues?
>
> -Denis
>
> On Wed, Dec 6, 2017 at 11:25 PM, Russell Senior <[email protected]>
> wrote:
>
>> There is an example on the wiki page:
>>
>>   https://sigrok.org/wiki/MASTECH_MAS345
>>
>> that says:
>>
>>   sigrok-cli --driver mastech-mas345:conn=/dev/ttyUSB0 --samples 10
>>
>> I would try that.  That might or might not be the right serial device
>> (i.e. ttyUSB0)... check dmesg, unplug/replug your cable and check
>> again, if necessary.
>>
>> On Wed, Dec 6, 2017 at 9:14 PM, Denis Heidtmann
>> <[email protected]> wrote:
>> > I agree completely.  I have downloaded sigrok-cli.  Now I have to try to
>> > understand how to use it.  (I feel a bit overwhelmed.)
>> > Where do I put the driver? Is output/input with respect to the external
>> > device or the software?  I assume the device, judging by the longer list
>> of
>> > output formats.  What is the protocol?  Do  I need to know, or will the
>> > driver decide?
>> >
>> > sigrok-cli -V
>> > sigrok-cli 0.5.0
>> >
>> > Using libsigrok 0.3.0 (lib version 2:0:0).
>> > Using libsigrokdecode 0.3.0 (lib version 2:0:0).
>> >
>> > Supported hardware drivers:
>> >  .
>> > .
>> > .
>> >   mastech-mas345       MASTECH MAS345
>> >  .
>> > .
>> > .
>> > Supported input formats:
>> >   binary               Raw binary
>> >   chronovu-la8         ChronoVu LA8
>> >   csv                  Comma-separated values (CSV)
>> >   vcd                  Value Change Dump
>> >   wav                  WAV file
>> >
>> > Supported output formats:
>> >   analog               Analog data
>> >   ascii                ASCII
>> >   binary               Raw binary
>> >   bits                 Bits
>> >   chronovu-la8         ChronoVu LA8
>> >   csv                  Comma-separated values (CSV)
>> >   gnuplot              Gnuplot
>> >   hex                  Hexadecimal
>> >   ols                  OpenBench Logic Sniffer
>> >   vcd                  Value Change Dump (VCD)
>> >
>> > Supported protocol decoders:
>> >   avr_isp              AVR In-System Programming
>> >   can                  Controller Area Network
>> >   dcf77                DCF77 time protocol
>> >   ds1307               Dallas DS1307
>> >   edid                 Extended Display Identification Data
>> >   guess_bitrate        Guess bitrate/baudrate
>> >   i2c                  Inter-Integrated Circuit
>> >   i2cdemux             I²C demultiplexer
>> >   i2cfilter            I²C filter
>> >   i2s                  Integrated Interchip Sound
>> >   ir_nec               IR NEC
>> >   ir_rc5               IR RC-5
>> >   jtag                 Joint Test Action Group (IEEE 1149.1)
>> >   jtag_stm32           Joint Test Action Group / ST STM32
>> >   lm75                 National LM75
>> >   lpc                  Low-Pin-Count
>> >   maxim_ds28ea00       Maxim DS28EA00 1-Wire digital thermometer
>> >   midi                 Musical Instrument Digital Interface
>> >   mlx90614             Melexis MLX90614
>> >   mx25lxx05d           Macronix MX25Lxx05D
>> >   mxc6225xu            MEMSIC MXC6225XU
>> >   nunchuk              Nintendo Wii Nunchuk
>> >   onewire_link         1-Wire serial communication bus (link layer)
>> >   onewire_network      1-Wire serial communication bus (network layer)
>> >   pan1321              Panasonic PAN1321
>> >   parallel             Parallel sync bus
>> >   rgb_led_spi          RGB LED string decoder (SPI)
>> >   rtc8564              Epson RTC-8564 JE/NB
>> >   sdcard_spi           Secure Digital card (SPI mode)
>> >   spi                  Serial Peripheral Interface
>> >   tlc5620              Texas Instruments TLC5620
>> >   uart                 Universal Asynchronous Receiver/Transmitter
>> >   usb_packet           Universal Serial Bus (LS/FS) packet
>> >   usb_signalling       Universal Serial Bus (LS/FS) signalling
>> >   xfp                  10 Gigabit Small Form Factor Pluggable Module
>> (XFP)
>> >   z80                  Zilog Z80 CPU
>> >
>> >
>> > On Wed, Dec 6, 2017 at 3:17 PM, Russell Senior <
>> [email protected]>
>> > wrote:
>> >
>> >> The sigrok route is probably a better investment of your time than a
>> >> vendor-software horror show, imho.
>> >>
>> >> On Wed, Dec 6, 2017 at 3:02 PM, Denis Heidtmann
>> >> <[email protected]> wrote:
>> >> > here is the link:
>> >> >
>> >> > https://sigrok.org/wiki/Multimeter_ICs#Metex_14-byte_ASCII
>> >> >
>> >> > I would need to study it and educate myself on how to make use of it.
>> >> >
>> >> > -Denis
>> >> >
>> >> > On Wed, Dec 6, 2017 at 2:29 PM, Denis Heidtmann <
>> >> [email protected]>
>> >> > wrote:
>> >> >
>> >> >> I have found this:
>> >> >> Protocol
>> >> >>
>> >> >> The protocol is (partially) documented in the vendor software's
>> "Help"
>> >> >> window (seems to apply to MAS343, MAS344, and MAS345; the M9803R
>> >> protocol
>> >> >> is different).
>> >> >>
>> >> >> See Multimeter_ICs#Metex_14-byte_ASCII for the DMM IC protocol.
>> >> >>
>> >> >> I looked in the software's help window, but with the sw I have there
>> is
>> >> no
>> >> >> discussion of protocol.  Maybe the note above is referring to other
>> >> >> software.  The MAS344 is not a current instrument.
>> >> >>
>> >> >>
>> >> >> On Wed, Dec 6, 2017 at 2:15 PM, Russell Senior <
>> >> [email protected]>
>> >> >> wrote:
>> >> >>
>> >> >>> Have you googled at all about the protocol?  You might be able to
>> just
>> >> >>> talk ASCII at it from Linux and get what you need.
>> >> >>>
>> >> >>> On Wed, Dec 6, 2017 at 1:22 PM, Denis Heidtmann
>> >> >>> <[email protected]> wrote:
>> >> >>> > I want to use a DMM with a serial connection.  The sw for the DMM
>> is
>> >> for
>> >> >>> > windows. It runs under Win2k (guest) on the desktop which has a
>> >> serial
>> >> >>> > port.   Is it possible to get it to run under Win2k (guest) on the
>> >> >>> laptop
>> >> >>> > which does not have a serial port?  I purchased a Sabrent usb to
>> >> serial
>> >> >>> > adapter that I hoped to use for this.
>> >> >>> >
>> >> >>> > I expect the problem is that I cannot get VB to pass the virtual
>> com
>> >> >>> port
>> >> >>> > data from the guest to the usb port in the host (ubuntu).  If
>> this is
>> >> >>> > impossible or too difficult to be practical I will pursue linux sw
>> >> for
>> >> >>> the
>> >> >>> > DMM, although I may run into a similar problem.  The DMM is
>> Mastech
>> >> >>> MAS-344.
>> >> >>> >
>> >> >>> > Thanks for any clues.
>> >> >>> >
>> >> >>> > -Denis
>> >> >>> > _______________________________________________
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>> >> >>
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