Re: Data from a serial port
On Sat, Oct 4, 2014 at 9:54 AM, Jerry Stuckle <jstuckle@attglobal.net> wrote:
> On 10/3/2014 8:19 PM, Joel Rees wrote:
>> On Sat, Oct 4, 2014 at 5:52 AM, Jerry Stuckle <jstuckle@attglobal.net> wrote:
>>> On 10/2/2014 8:24 PM, Ethan Rosenberg wrote:
>>>> [...]
>>>
>>> In addition to Dan's comments - is your cable OK? Do you need a
>>> straight-through cable or a cross-over cable? Does the terminal
>>> require/honor DSR/TSR and RTS/CTS? If so, are these lines active?
>>>
>>> You may need a breakout box on the cable to see what's happening on the
>>> lines.
>>
>> If, for some reason, you can't get a breakout box, you may be able to
>> do basic tests on the cable with a multimeter (ohm-meter or
>> connectivity function), the pin diagrams, some patience, and maybe an
>> extra pair of hands (if you can't find small-mouth alligator clips or
>> pin clips). Just don't tell whoever handles requisitions/budget unless
>> they understand that patience costs time and money when doing things
>> like this. You have to be really careful to keep the leads from
>> slipping, and not noticing a slipped lead can cost hours of
>> unnecessary work.And there are tests you really don't want to try
>> without a breakout box or the equivalent.
>>
>
> Why couldn't he? They're cheap, i.e.
> http://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_10001_14285_-1.
>
> Note if he's using DB9 connectors he would need a pair of DB9-DB25
> connectors. But they are also cheap.
Uhm, maybe he has a multimeter now, and doesn't want to wait for
overnight shipping or take the time to run down to a supply house
downtown or even wait for said supply house to do a same-day delivery.
Or maybe finances at the company are really, really tight right at the moment.
Now, of course, if the supply house is next door, and his company is
okay with people bringing in tools paid for out-of-pocket, going and
getting it would be a good excuse to take a half-hour break anyway
(assuming no lines at the supply house).
My point was simply that connectivity checks don't need a breakout box.
Breakout boxes do make them more convenient, and quicker, and give
more reliable results. Not to mention enabling more in-depth testing,
especially if you have an oscilloscope with data capture.
I'm not arguing with you on this one, Jerry, I was just offering an
alternative. Not a great alternative, but maybe a useful one.
--
Joel Rees
Be careful where you see conspiracy.
Look first in your own heart,
and ask yourself if you are not your own worst enemy.
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