Re: GPS problem

From: V Green (vanceg_at_nowhere.net)
Date: 09/04/04 

Date: Sat, 4 Sep 2004 09:09:29 -0700

"David Hettel MS MVP - Mobile Devices" <dhettel@fuse.net> wrote in message
news:%23Ezr2NpkEHA.1348@TK2MSFTNGP15.phx.gbl...
> Perhaps I am missing something here. The Garmin cable to the PC is a
simple
> cable, no electronics in it. It should show continuity on each line/pin.
> From what others have posted the ASUS A620 has a ttl to RS232 converter in
> it. I would not expect it to show continuity between pins. (And I would
not
> be surprised if you happen to check between pins on the same connector
(eg.
> between pins on the RS232 connector) that you have blown the converter
> within the ASUS A620 cable.

Not likely if manufactured properly.

Don't forget, the RS-232 spec allows for voltage
swings of up to +/- 25VDC.

Most if not all DVMS use a 9V rectangular battery
as power source, hence the max. voltage that should
appear on the leads when it's set to any resistance scale
should not exceed that value.

Now, if you grabbed your Megger to do the checking, well...

It should be expected that some so-called "RS-232"
devices are manufactured on the ASSUMPTION that it will
NEVER ACTUALLY be hooked (as in a PC environment)
to an honest-to-God older RS-232 device like a TTY
where it'll see the higher voltages
allowed by the spec and fudge the circuitry
such that damaging it with a DVM may be possible.

ESD would be my choice of mechanism that destroyed
your cable (if it actually has been).

> The convert is protected when power up, but
> applying power to pins on it when it is not power up is a very bad thing
to
> do, generally.
>
> Here in the States I would need both a null modem adapter and also a
gender
> changer. Most PocketPCs have two versions of a serial cable. One designed
> for ActiveSyncing which would require both the gender changer and null
modem
> adapter from Radio Shack. The other type, would be to add a serial
> peripheral to the PocketPC (Which is harder to come by, and in my
experience
> generally short say 6 inches or so) and will have the same 9 pin connector
> as on your PC.
>
>
>
> --
> David Hettel
> Microsoft MVP Mobile Devices
>
> This posting is provided "as is" with no warranties, and confers no
rights.
> You assume all risks for your use.
>
> Handhelds, mobile: http://www.geekzone.co.nz
> Bluetooth guides: http://www.geekzone.co.nz/content.asp?contentid=449
>
> "AlanS" <news@remove.abyz.fslife.co.uk> wrote in message
> news:chcdhm$8dk$1@newsg2.svr.pol.co.uk...
> >
> > "Darren Griffin - PocketGPS" <darren@pocketgpsworld.com> wrote in
message
> > news:OKmjWgkkEHA.3848@tk2msftngp13.phx.gbl...
> >> AlanS wrote:
> >> > Thanks. I'd ordered via ukorder2@pc-mobile.net and had emailed them,
> >> > but no response in over 24 hours, and it's now the weekend. I'll try
> >> > a copy to the address you give too.
> >>
> >> Or post in our PC-Mobile Forum which is moderated by them
> >>
> >
<http://www.pocketgpsworld.com/modules.php?name=Forums&file=viewforum&f=49>
> >> They have an excellent reputation for service so have no fear that they
> > will
> >> replace the cable.
> >> --
> >> Darren Griffin
> >> PocketGPSWorld - www.pocketgpsworld.com
> >> The Premier GPS Resource for News, Reviews and Forums
> >>
> >>
> >
> > Thanks.
> >
> > That would be 3 messages agent about this them in under 2 days, and at
the
> > weekend too, plus this newsgroup would make 4! (1 to them in HK, 1 to
the
> > UK
> > already sent).
> >
> > I don't really want to give the wrong impression (that I'm swamping them
> > with emails/postings all over the place!) so I'll hang on a few more
days
> > before trying there, but thanks for the link. I'm really like to confirm
> > if
> > it is actually faulty first, then how to get a working replacement
> > (preferably checked by them- someone/anyone - for operation first).
> >
> > I would like to double check the pin continuity though- to know if the 3
> > Garmin data pins do show continuity on a working cable in this way (and
> > which pins connect to which if possible- but just the continuity would
> > confirm the status of my cable).
> >
> > Many thanks for the link.
> >
> >
> > As an aside I'd like to recommend the battery box that they sell. It
seems
> > smaller than I had expected, and is pretty neat and well built. There is
a
> > screwhole to hold the top cover in place but no screw provided! It seems
> > solid enough without a screw in place, and it looks like a fairly small
> > self
> > tapper would be needed. If the screw was in place I'd need the
screwdriver
> > with me on travels to allow battery changes so it's probably best not
> > used-
> > it doesn't seem to work well enough without the screw.
> > When connected and switched on it charges the internal battery (as if
the
> > pda is connected to the mains), and one set of 4 x 1500 mAH NiMH
batteries
> > have given 2 charges from around 60% up to now. NiMH AA batteries can be
> > found with over 2000 mAH now- I've seen 2150 mAH ones.
> > It seems as if it will be a good convenient alternative to a travel
> > charger-
> > smaller and lighter too.
> > The cable seems quite short- but actually is about 12 inches long. A
nice
> > and inexpensive accessory I certainly recommend, certainly not just for
> > GPS
> > users but offers an easy, portable and inexpensive way to extend the
pda's
> > battery life.
> >
> >
> >
>
>

Relevant Pages

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