[time-nuts] TBOLT communication

[Predrag Dukic]

I had the same problem with some other devices, and I took apart 
several converters.
Most of them were unable to generate sufficient levels for a proper 
communication with rs232.
Internal charge pump was generating  +-6V instead of +-12 or +-15 
that is normal for rs232.

Putting additional +-12 V source on the psu pins of the converter 
chip might help.


Predrag Dukic




At 10:58 24.9.2008, you wrote:
>Hi,
>I have just spent a week or two trying to talk to a Trimble Thunderbolt.
>I have a laptop running VISTA, about which there is little to say.
>The laptop has no serial ports, but I have some USB/Serial converters
>that successfully run
>my HP 3815A and a Samsung GCRU/D, and also communicate with my HOBO
>loggers.
>The USB/Serial converters are a little difficult to use, sometimes
>hanging, necessitating
>unplugging and plugging back in. They get assigned to various Port
>numbers but tend to keep
>the same number from day to day. The ports can be configured in the
>management function.
>However the TBOLT refuses to talk to the converter, to the extent
>that I thought that I must have
>damaged the TBOLT.
>Today, as a last resort, I remembered an old PC, dragged it out and
>stoked it up, and to my delight
>the TBOLT monitoring program ran without difficulty under Windows
>2000 with a conventional serial port.
>Now I vaguely remember talk about RS232 communications and the need
>for pull up or down
>resistors and supplies, but searching the archives I could find
>nothing relevant.
>Can anyone tell me how I could run the TBOLT off a USB/Serial converter?
>cheers, Neville Michie
>
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