etrex usb problems

redwoodsmtbiker · 12-12-03, 10:21 AM

Hi-

I'm new here. I just bought an Axim to go with my Etrex Venture, realizing there are some well documented communication problems. Now I'm having my first regrets. The Axim is USB and I bought a connector from www.pc-mobile.net. I followed their instructions on http://pc-mobile.net/aximnote.htm, starting my software (OziExplorerCE) first, before connecting my Garmin, but they still don't talk to each other. I've read all I can on multiple boards. It seems there is a lot of discussion re: serial cables, but not much on usb. I tried taping the data in pin on the GPS, as has been suggested in another forum. I tried clearing Activesync from memory too. Nothing works. Very frustrating. Maybe I've got a bad cable. Any suggestions?

Rich

Podge · 12-12-03, 10:51 AM

Firstly, I'm going to assume you have an AXIM X5 so you are not using USB you are tring to use serial. Check the following.

Your software should be configured to com1 4800
You garmin should be configured for NMEA(out) you'll find this in the settings area.

redwoodsmtbiker · 12-12-03, 11:34 AM

Sorry, should have said...Yes, it is an X5. But it is not a serial connection. It is USB. Everything is configured as you stated.

JakeRich · 12-12-03, 12:23 PM

The X5 does not support USB communications as a host. If you bought a cable from PC-Mobile, it is converting the USB to serial. You should read the posts on serial and etrex. It is complex.

redwoodsmtbiker · 12-12-03, 12:34 PM

Yes, I've read everything I can find on multiple boards about the serial cable solutions, but I still have no idea where to go with the USB issue.

Lionclaw · 12-12-03, 04:55 PM

I was able to connect my venture to my axim. Had to use the serial cable with the axim, serial cable with the venture, and a null modem adapter and gender bender in the middle. Then I had to put a piece of tape over one of the pins on the venture.

I had it working with pocket streets, but I didn't try ozi.

JakeRich · 12-12-03, 09:46 PM

The USB standard defines two types of ports: Host and Device. You cannot connect a Device to another Device. There must be a Host to support a Device. PCs act as Host. The Axim is a Device. You cannot connect the Axim to anything but a PC through USB.

To get around that limitation for external communications, Dell came out with a so-called Serial cable that converts the USB Device signals to RS232 Serial signals. However, the Dell cable was specifically designed to connect to a PC RS232 port that puts power on a certain Serial interface pin. That power on that pin then activates the signal conversion process in the Dell cable.

So, PC-Mobile then reverse engineered the Dell cable to create a serial cable (or engineered their own) to connect to GPS units. they replaced the standard RS232 connector with GPS-specific connectors and did the wire-swapping needed to communicate properly. Basically, the PC-Mobile cable replaces the Null Modem and etrex serial cable that would be required if all you had was the Dell cable.

Ok, all of that was to lead to this statement: Forget USB. You cannot communicate with the etrex using USB in any way. The PC-Mobile cable converts USB to Serial so your problem is entirely Serial. Read the boards here for how to trigger the Serial communications successfully.

redwoodsmtbiker · 12-12-03, 10:17 PM

Thanks. I'll give it a try, but I'm not that good of a tech person, and there are no "serial" connectors to mess with. There is the plug that goes into the base of the Axim. I don't see what I could do with that. Then there is the plug for the GPS. Maybe I could do something there. I tried taping the data in pin as someone suggested, but to no avail.

I do understand what you are saying about USB. I'm sitting here looking at the setup now. But all I've got to work with are those two connectors. I may just end up buying a serial cable for the Axim and do the null modem/gender bender thing. I have a serial cable for the GPS, but its not part of the pcmoble setup.

If this board will let me, I'll try to post a photo.

CLSCLS · 12-12-03, 10:35 PM

I own an Axim X5 and I just bought a cable from semons that connects my Garmin etrex directly to the bottom connector on my Axim. I have not bought the mapping software yet. Mapoplis Navigator for Pocket PC (download version) will probably be my choice ($89).
Does this software download into my Axim or my PC? and what's this all about with serial or USB ports? My Axim cradle connects to my computor with USB. Will this be an issue?
Sorry for the dumb questions by I'm learning as I go and would like to minimize my mistakes as best as possible.
Thanks,
Craig

redwoodsmtbiker · 12-12-03, 10:39 PM

Sounds like we could be in the same boat. You can download OziExplorerCE for free and see if your GPS will connect. There may be other free programs out there to try.

CLSCLS · 12-12-03, 10:56 PM

Now you guys have got me concerned
I own an Axim X5 and I just bought a cable from semons that connects my Garmin etrex directly to the bottom connector on my Axim. I have not bought the mapping software yet. Mapoplis Navigator for Pocket PC (download version) will probably be my choice ($89).
Does this software download into my Axim or my PC? and what's this all about with serial or USB ports? My Axim cradle connects to my computor with USB. Will this be an issue?
Sorry for the dumb questions by I'm learning as I go and would like to minimize my mistakes as best as possible.
Thanks,
Craig

JakeRich · 12-12-03, 11:29 PM

Please don't double post.

Now, to the questions:

The biggest issue with serial communications is that the way it is set up Activesync assumes that any communications on the Dell Axim bottom port is an attempt to sync through USB. Activesync then triggers a communications session at very high priority. Unfortunately, the GSP unit that is actually connected doesn't respond properly, but Activesync has no way to abort the attempt. The Axim slows to a crawl and has to be Soft reset (or worse) to recover.

Also, Dell only engineered the bottom port for USB as a device. To get to RS232 signals requires some voltage level and timing changes. To do that the Dell cable has a little board in it that has a chip that makes the change. Unfortunately Dell designed it with the requirement that a certain pin be held high to trigger the chip. It's no problem with the true RS232 port, but a big problem with the partial serial port on most GPS units because they don't provide that signal so the card doesn't start.

Ok, enough background. The process defined by PC-Mobile is to kill Activesync on the Axim, start the mapping software and get it to look at the serial port (COM1) for the signals and then connect the GPS to the Axim. That sequence blocks Activesync from seeing the signal and going into sync mode. I use that process every day and it works. My serial GPS is a Haicom, but I have used a Magellan as well.

Now, the serial cable from PC-Mobile is one-way, from the GPS to the Axim. If that is all you want to do, then just follow the procedure and it should work. IF you want to send signals TO the etrex from the Axim, then you need to read this thread. If you aren't handy with a soldering iron, print it out and take it to someone who is and see if they can help you.

A good program to test with is GPSViewer from Holux. You can download it from their web site for free. It allows you to see what the GPS is doing.

The Axim serial port is Com1, and NMEA standard is 4800 baud, so set that for the extrex, if you need to.

Mapopolis has an install program that runs on the PC and installs to the Axim through Activesync. After that you download the maps you want to the Axim and you should be ready to go. If you are a little more tech savvy, you can download the .cab file and copy it to the Axim and then doubletap it to run it to install.

Hope all that helps.

redwoodsmtbiker · 12-14-03, 08:31 PM

Hey guys, it works! I think I just finally did everything right, and in the right sequence. It helped that it finally stopped raining and I could actually get outside with it, since my eTrex apparently has no simulation mode. Thanks JakeRich for your help. I was ready to send my Axim back, but you convinced me it would work. I've used it successfully now with both OziCE and Pocket Streets.

JakeRich · 12-14-03, 09:45 PM

Great! I'm glad it worked out. Enjoy the GPS, I find it really a great use of the Axim.