Serial analyzers (was Re: VAX 11/730 quickie)

jwsmobile jws at
Wed Feb 24 13:20:26 CST 2016

On 2/24/2016 10:59 AM, Eric Smith wrote:
> On Tue, Feb 23, 2016 at 8:52 PM, jwsmobile <jws at> wrote:
>> For serial I use a Saleae 8 bit analyzer.
> [...]
>> You do have to use a level shifter with the thing because it is designed for
>> 3.3v logic and needs to be adjusted accordingly.
> The Saleae Logic Pro 16 (and probably the Logic Pro 8, but I haven't
> checked) are designed for an operating input voltage range of +/-10V,
> with an abs max rating of +/-25V. Saleae specifically states that it
> can be directly connected to RS-232.
We had the analyzers out "bleeding edge" and the originals were not 
differential and were not +5 safe.  They tolerated the differential 0-5 
we had at one point in the circuit, and the engineer I worked with said 
"hm, you are lucky" with that hookup.

I was not using the Pro, that is way late in their product line for me.

their newer 4 channel version does seem to also be differential and 
RS232 voltage level compliant.  (FWIW I was on RS485 differential, line 
levels same as RS232, but function not).

> The Logic Pro models are more expensive than the other (amateur?)
> models, but support analog input on all channels. I now use a Logic
> Pro 16 for most of my simple logic analyzer requirements, but still
> use an Agilent 16700 logic analyzer mainframe when I need more than 16
> channels.

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