[PLUG] com port in guest to usb in host (virtual box)

[Denis Heidtmann]

Here is the protocol description I recall finding:

MAS345:

data format: 7n2 at 600 baud (7 bits, no parity, 2 stop bits).
Control lines:
   DTR and RTS lines are used to power the TX line: RTS is clear
   for -12 supply; DTR is set for +12 supply. Data transmission is
   solicited sending whatever character to the RX line.
Data string format:
   MAS-345 sends a 14 bytes string with:
         <mode>< ><sign><value>< ><units><return>
   <mode>:  two bytes with the oerating mode: DC, AC, OH, CA, TE ...
   <sign>:  one byte with - or space
   <value>: five bytes with four digits and one decimal dot.
   <units>: four bytes with the units: mV, A, kOhm, nF ...
   <return>: '\r'
   One space is inserted between <mode> and <sign>, one between
   <value> and <units>.
   The data string (without the '\r') is sent to the output device.

On Sun, Dec 10, 2017 at 6:11 PM, Denis Heidtmann <denis.heidtmann at gmail.com>
wrote:

> The protocol I recall seeing documented was 7n2, 600 baud.  I must confess
> I do not know how to talk directly over serial.  I tried Google, but there
> were too many options and opinions.  What do you recommend for this simple
> task?
>
> On Sun, Dec 10, 2017 at 3:01 PM, Russell Senior <russell at personaltelco.net
> > wrote:
>
>> Try talking to the DMM directly over serial.  The protocol description
>> says:
>>
>>   Various multimeters from Metex (and rebadged ones) use this common
>> 14-byte packet based ASCII protocol. The actual multimeter ICs in the
>> devices have different names (e.g. "MASTECH M343-01" or "Metex
>> KS57C2016") but they all use the same common protocol format.
>>
>>   The serial port settings can vary from device to device, e.g.
>> 600/1200 baud, 7n2, RTS low, DTR high.
>>
>> If you get the serial parameters right, you ought to be able to talk
>> directly at it (e.g. send a D and get a string of bytes).  Maybe you
>> can snoop the serial with an oscilloscope while running the vendor
>> interface software and figure out the baud,et al.
>>
>> On Sun, Dec 10, 2017 at 2:08 PM, Denis Heidtmann
>> <denis.heidtmann at gmail.com> wrote:
>> > Thanks for the -help.  I got part of that -help when I entered an
>> incorrect
>> > option, but somehow missed the -- entries at the end.  Here is what I
>> get:
>> >
>> > denis at denis-ThinkPad-L420:~$ sigrok-cli --driver
>> > mastech-mas345:conn=/dev/ttyUSB0 --scan
>> > The following devices were found:
>> > mastech-mas345 - MASTECH MAS345 with 1 channel: P1
>> >
>> > denis at denis-ThinkPad-L420:~$ sigrok-cli --driver
>> > mastech-mas345:conn=/dev/ttyUSB0 --show
>> > mastech-mas345 - MASTECH MAS345 with 1 channel: P1
>> > Supported driver options:
>> >     conn
>> >     serialcomm
>> > Supported configuration options:
>> > denis at denis-ThinkPad-L420:~$
>> >
>> > Additionally I tried:
>> > denis at denis-ThinkPad-L420:~$ sigrok-cli --driver
>> > mastech-mas345:conn=/dev/ttyUSB0 --loglevel 5
>> > sr: libsigrok loglevel set to 5.
>> > sr: backend: Sanity-checking all drivers.
>> > sr: backend: Sanity-checking all input modules.
>> > sr: backend: Sanity-checking all output modules.
>> > srd: libsigrokdecode loglevel set to 5.
>> > Usage:
>> >   sigrok-cli [OPTION...]
>> > snip...
>> >
>> > I also tried the --output-file but nothing.  I found that I could not
>> enter
>> > more than one option at a time---I tried --scan and --show but only the
>> > first one was responded to.
>> >
>> > BTW, recall that this instrument worked as expected using the vendor's
>> > windows sw on the desktop, where I have a serial port.  So I do not
>> suspect
>> > the hardware outside the laptop.
>> >
>> > These results are encouraging, but no cigar.
>> >
>> > -Denis
>> > _______________________________________________
>> > PLUG mailing list
>> > PLUG at pdxlinux.org
>> > http://lists.pdxlinux.org/mailman/listinfo/plug
>> _______________________________________________
>> PLUG mailing list
>> PLUG at pdxlinux.org
>> http://lists.pdxlinux.org/mailman/listinfo/plug
>>
>
>