Cambridge 302 USB Port

I have a few questions regarding the USB port on the later Cambridge 302. The Cambridge manual leaves much to be desired in explaining what it can do.

Is the USB port supposed to supply power to a PDA or other device?

Are you able to transfer files both ways with a PDA or PocketPC (logs and waypoints, etc.) or does the port only work with a laptop?

What is the best way to use both the 303 and a PDA connected to the 302?

Hi Karl,

Good questions. Please see my answers below.

Best Regards,

Paul Remde
Cumulus Soaring, Inc.

"Karl Kunz" wrote in message
news:16601193.26.1323215405491.JavaMail.geo-discussion-forums@pruu5...
I have a few questions regarding the USB port on the later Cambridge 302.
The Cambridge manual leaves much to be desired in explaining what it can
do.

Is the USB port supposed to supply power to a PDA or other device?

- No. The USB port is only for connection to a PC. The PC is the master
and the 302 is the slave. Since PDAs are generally also USB slaves, the 302
can't talk to them through the USB port.


Are you able to transfer files both ways with a PDA or PocketPC (logs and
waypoints, etc.) or does the port only work with a laptop?

- You can transfer files to and from a 302 using a PDA - but only when the
PDA is connected to the 302's RS-232 port (the one with the 9-pin
connector). The USB port works only with PCs.


What is the best way to use both the 303 and a PDA connected to the 302?

- Connect the PDA to the 9-pin (DB-9) port and connect the 303 to the RJ
(phone jack) port. They can both be used at the same time.

Thanks Paul. Will the DB-9 port provide power to the PDA?

Will the DB-9 port provide power to the PDA?

- Yes and no. The power source from C302 is problematic, especially
when the battery on your PDA is charging. I have seen my C302 freezing
and working erratically under those circumstances. It’s better if you
provide the power via the power converter directly from your glider's
battery.
The USB port on the C302 is pretty much useless since you have to
switch communication between serial and the USB with a dip switch
which is located at the back of the C302. In my case its still
requires taking the canopy off to reach the back side of the C302
anytime I like to use the USB port. You can also download flight logs
and declare the task via the PDA serial communication and gliding
softwa Winpilot(and a small program you can obtain for free from
Cambridge aero) or the Connect me from seeyou.

GK

If you use a separate power source as you describe, how do you tie it into the serial cable?

On Dec 7, 11:49*am, Karl Kunz wrote:
If you use a separate power source as you describe, how do you tie it into the serial cable?

Serial communication doesn’t carry power over the same media as the
communications. So Pins: 2 is RX and Pin 3 is TX. Pins 5 and 6 are
5VDC and Ground (if I remember correctly). Tim has the plug diagram on
his web site. You can purchase a premade converter for the PDA, if you
purchase the Oudie it already comes with a premade cable. Or you can
make one yourselves

On Dec 7, 10:39*am, GK wrote:
Will the DB-9 port provide power to the PDA?

- Yes and no. The power source from C302 is problematic, especially
when the battery on your PDA is charging. I have seen my C302 freezing
and working erratically under those circumstances. It’s better if you
provide the power via the power converter directly from your glider's
battery.


GK

I have heard this same message on several occasions about the 302 not
being able to supply enough power to a PDA with a low battery and then
causing issues. This is not my experience. I am using a 302 with a
HP2215 that at times has a totally flat battery when I plug it into
the cradle (and the 302's RS-232 connector) at the field. I have
never had an issue. Might this have to do with the vintage of the
302? Mine is about 6 years old without the USB connector.

BTW: I store everything on a CF or SD card in the HP2215 so I don't
keep it plugged in and don't care if the PDA looses its memory
contents or not. Its a better way to go IMHO.

On Dec 7, 9:39*am, GK wrote:
Will the DB-9 port provide power to the PDA?

- Yes and no. The power source from C302 is problematic,

No problem with mine powering an Aero 1530 for the last 9 or so
years. Of course it doesn't normally need a back light like some
other PDAs. Although I try to have the PDA fully charged before use
in the glider it isn't always.

Andy

Hi,

I'm sorry, but I must respectfully disagree with your comment about the 302
not being able to power a PDA. I have used many different PDAs with a 302
for years with no problems. I think customers have problems when they
connect a PDA with the PDA's battery low. PDAs with low batteries can draw
a LOT of current (over 1 A). The 302 can supply plenty of current for all
PDAs and PNAs I've seen - as long as they are fully or nearly fully charged.

Paul Remde
Cumulus Soaring, Inc.

"GK" wrote in message
...
Will the DB-9 port provide power to the PDA?

- Yes and no. The power source from C302 is problematic, especially
when the battery on your PDA is charging. I have seen my C302 freezing
and working erratically under those circumstances. It’s better if you
provide the power via the power converter directly from your glider's
battery.
The USB port on the C302 is pretty much useless since you have to
switch communication between serial and the USB with a dip switch
which is located at the back of the C302. In my case its still
requires taking the canopy off to reach the back side of the C302
anytime I like to use the USB port. You can also download flight logs
and declare the task via the PDA serial communication and gliding
softwa Winpilot(and a small program you can obtain for free from
Cambridge aero) or the Connect me from seeyou.

GK

Paul,

Here's the deal: the back of my Ipaq 3950 says 5VDC, 2 amps.

The 302 docs tell us we are limited to 0.9 amp out of the 302.

You, and others, have led us into a marginal solution. I think you
ought to quit doing that :-).

I have about 500 hours of *mostly* trouble free PDA operation off my
302... because I *mostly* remember to have the the PDA at full
charge. I've sometimes forgotten (mostly during a two day drive
somewhere) and then had mysterious problems with the 302 (mostly 1200
miles from home). I finally read the manual (again). It's easy to
miss stuff in the 302 manual because of the way it isn't really
organized.... but here it is (smites brow).

The correct solution for anyone with a PDA is to ensure that the power
supply is up to the task. The 302 isn't by any reasonable engineering
definition.

Here's a $12 start to a proper engineering solution
http://www.murata-ps.com/data/meters...8sr-2a_a00.pdf

Get 'em at Mouser. Input fuse is a good idea.

-Evan Ludeman / T8


On Dec 7, 5:10*pm, "Paul Remde" wrote:
Hi,

I'm sorry, but I must respectfully disagree with your comment about the 302
not being able to power a PDA. *I have used many different PDAs with a 302
for years with no problems. *I think customers have problems when they
connect a PDA with the PDA's battery low. *PDAs with low batteries can draw
a LOT of current (over 1 A). *The 302 can supply plenty of current for all
PDAs and PNAs I've seen - as long as they are fully or nearly fully charged.

Paul Remde
Cumulus Soaring, Inc.

"GK" wrote in message

...
Will the DB-9 port provide power to the PDA?

- Yes and no. The power source from C302 is problematic, especially
when the battery on your PDA is charging. I have seen my C302 freezing
and working erratically under those circumstances. It’s better if you
provide the power via the power converter directly from your glider's
battery.
* * *The USB port on the C302 is pretty much useless since you have to
switch communication between serial and the USB with a dip switch
which is located at the back of the C302. In my case its still
requires taking the canopy off to reach the back side of the C302
anytime I like to use the USB port. You can also download flight logs
and declare the task via the PDA serial communication and gliding
softwa Winpilot(and a small program you can obtain for free from
Cambridge aero) or the Connect me from seeyou.

GK