[time-nuts] Rapco 1804M - serial problems?

David J Taylor david-taylor at blueyonder.co.uk
Tue Oct 18 03:56:00 EDT 2011

> You might collect a pile of errors and analyze the bit level changes.

Yes, I could do that, were it critical.

> I think some of your errors were / changing to a ?.  That's hex 2F 
> changing
> to 3F, or picking the 10 bit.  How many of the other errors did the same
> thing?
> I think serial ports are least significant bit first, so a scope would 
> see
> 11110100 changing to 11111100.  That would be a reasonable error on a 
> serial
> port if the high-low-high transition was slow and didn't get low enough.
> (But 4800 is really slow and you said the cable was short.  Any problems
> should be obvious on a scope.)

There are no obvious problems, Hal.

> Do you have any other serial ports where you could try it?  How about a
> serial-USB dongle?  Or maybe even a shorter cable?

Unfortunately I'm out of serial ports.  The computers with more than one 
were retired some time back, and the others all have GPS PPS connections. 
It's actually running on a USB dongle right now.

I'm going to contact the seller of the unit and see what he suggests - he 
may even want to replace the unit.

Thanks again for your interest.

SatSignal software - quality software written to your requirements
Web:  http://www.satsignal.eu
Email:  david-taylor at blueyonder.co.uk 

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