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Serial Port?


dollarman

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Who the heck still puts a serial port on PC's and why does Garmin still offer this antiquated means of connecting to PC?

 

I have 7 functioning machines on the table in front of me (both PC and Sparc hardware) and only one came stock with USB (a p900). I'll continue to use them until they die or until I suddenly have the funds to replace them with newer gear. When I do replace them I'll snag some 1GHz machines used from folks who think they need a 3Ghz machine to surf the web and look at spreadsheets in excel.

 

I did buy a serial/usb converter to tie my legend into my PC at work.

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Garmin still offers it because it's still the standard for NMEA and because it works. You can connect any two devices via RS232 serial connections, but not USB. With USB one must be a host, which requires lots of additonal electronics, and thus cost. For example, you cannot connect a USB GPS to any PDA, only a PC. I want to connect my GPS to my Palm, and that's not possible via USB. USB isn't universal, and it's not truly a bus. It's an abortion, enabled by marketing pressure, not by quality. My cheap Belkin adapter works great for everything I've tried, including my Garmin, my old Palm, and whatever other serial device I want to connect. Serial is old, but it's reliable and works for everything.

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If you are looking for GPS solutions of the PDA or Laptop variety, I would strongly consider the Bluetooth option. There are LOTS of Bluetooth GPS modules out there, several well under $100. In addition, many of them feature the latest SiRF chipsets which are indeed much more sensitive than older equipment. I placed my Wintec 4-in-1 Bluetoth GPS right next to my Garmin E-trex in my basement window and the Wintec easily aquires a solid fix whereas the Garmin can barely see a satellite or two from that location.

 

The other thing I really like about the Bluetooth option over either USB or Serial is NO CABLES!!. I just chuck the little GPS "hockey puck" up on the dash and the laptop/PDA can be anywhere (I typically have one of the passengers running the navigation on long trips. )

 

If your laptop or PC doesn't come with built-in Bluetooth, you can buy a Bluetooth USB dongle for around $20 from your local computer store. The included drivers and software will make it look like an ordinary comm port so you can use it with Delorme Street Maps or any other software that does NMEA over a comm port. The only issue there that I've heard of is one report that Microsoft's Streets software didn't allow a high enough baud rate in the case of one installation. But I view that as an M$ problem.

 

In my case, I use my bluetooth enabled cell phone (many are these days) as the "readout" for the GPS. I just wrote a little Java app that runs on the phone designed especially for geocaching that allows me to enter and mark waypoints and select them from a list. Then it just gives me HEADING (as opposed to bearing) and distance info. As a pilot, I much prefer working in terms of headings. I've seen my children go off in the wrong direction using the BEARING pointer on the E-trex. That can "lie" to you if you change direction until it figures out your new ground track.

 

There are a number of navigation programs out there for various bluetooth enabled cell phones and PDA's. Once you've been liberated from the CABLE hassle of either USB or serial, you never want to go back. I'm even going to sew a little pocket in one of my ball caps to hold the GPS "puck" and use my cell phone when geocaching. That way I won't have to fight the kids for the E-trex (grin). Besides, when you are walking in the woods with your PDA, cables snag on every branch.

 

Give Bluetooth a try. You'll like it!

Edited by dpbabcock
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If I read your post correctly, I think you've transposed heading and bearing. Heading is the direction you're moving, bearing is the true direction to the destination, which is what you want. I do agree that bluetooth is the way to go if you're connecting a GPS to a PDA. If you already have a high-end GPS and want to make it bluetooth-capable, PC-Mobile sells an adapter that will work with just about any GPS. I connect it to my Legend and my RS Digitraveler, which was produced long before bluetooth was even conceived.

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I also bought a Belkin serial to USB adaptor for my camera around 2004. It did not work, it did not recognize my camera. After posting this problem on several forums one person mentioned that some serial to USB adaptors do not use all the pins, whereas your camera needs one or more of those disconnected pins.

 

If you install the correct USB drivers for your GPS and it still does not work, it just might be the serial 2 USB adaptor.

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I had the same problem and finally added a serial port to my pc. I got one off ebay for $12.98 delivered. Easy to install. Wish I had known about it before I bought the adapter and spent hours trying to get it going. Good luck.

 

Did the same thing fixed the problem

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If I read your post correctly, I think you've transposed heading and bearing. Heading is the direction you're moving, bearing is the true direction to the destination, which is what you want. I do agree that bluetooth is the way to go if you're connecting a GPS to a PDA. If you already have a high-end GPS and want to make it bluetooth-capable, PC-Mobile sells an adapter that will work with just about any GPS. I connect it to my Legend and my RS Digitraveler, which was produced long before bluetooth was even conceived.

 

Actually, I think I got it right. Heading is with respect to North (either magnetic as when I'm flying using the compass for reference) or True (as when I'm computing relative to meridians. The HEADING from where I am to where I want to be will always be the same (think of your Directional Gyro). So if I'm Southeast of my target, the HEADING will ALWAYS be NW. However, the Bearing is relative to where my nose is pointed. So if my HEADING is say 315 degrees, my BEARING will be 45 degrees to the RIGHT if I'm westbound but if I happen to be pointed east the bearing would be 135 degrees to the LEFT. Bearing is relative to your nose. Heading is relative to "North" (either magnetic or true depending upon your reference.

 

Practically, when you are trekking through the woods using the directional arrow on the Garmin E-trex, it points RELATIVE to the unit as you hold it in front of you and walk a straight track. But if you start turning with it and don't give it time to establish a new ground track, it will lead you astray. For a simple case, walk a bit in a straight line then stand still. You can rotate the GPS around in your hand and the arrow will just stay put. The GPS can't "know" which way it's going if you aren't moving. And even then it assumes you are walking with the "top" of the gps pointing forward. If you walk holding it "backwards" in your hand it will point in the opposite direction. That's because it doen't "know" how you are holding it.

 

So when I'm in the woods especially when you get in close and you are turning and looking, I want the readout to give me the HEADING, NOT the relative bearing. I generally will know which direction is "North". If in doubt, take a compass. The little 4-in-1 unit I mentioned actually has a built in magnetic compass LED that will glow solid when the unit is oriented to magnetic north. But generally sun position will give me enough directional orienation. I've seen my kids chase off following the bearing arrow on the E-trex as it swings wildly because they keep changing their ground track. As a pilot, I want the unit to tell me that my target is at 315 degrees at 500 feet regardless of which way I happen to be walking at the moment or facing and regardless of how I hold the unit. I'll get to the cache much quicker that way, especially when I'm having to weave through the woods picking my path.

 

I guess I'm using HEADING in the same since as one thinks about it with respect to the DG in an aircraft. If I make my AC HEADING agree with the HEADING info on my GPS, I'll be flying TOWARD the target (assuming no wind and a DG that is set properly.) The HEADING from my present position to the target doesn't change but If I'm doing steep turns around a point, the BEARING changes constantly. Heading to target doesn't depend upon which way I'm pointing at the moment. Bearing does. At least that's my concept of it. Hence the term: "relative BEARING." It's relative to the nose of the craft.

 

Anyway, what I wanted out of my software was a readout that says "315 degrees" when the target is NW of me regarless of which way I happened to be walking or facing at the moment. In fairness, the E-trex DOES give that kind of info but for novices, it is very easy to fixate on the arrow without taking into account the other readouts (like the changing compass card background on the display). Having a simple decimal readout of the heading offers fewer opportunities for misunderstanding. This is especially critical during the last few feet when the GPS is "dithering" due to the leaf canopy and you are pacing back and forth in the area doing the "hotter-colder" mental averaging of the distance readout. With the E-trex I keep having to remind the kids to ignore the arrow and just focus on the distance readout, walk a few steps in some direction and see if they are generally getting "hotter" (closer) or "colder" (farther away.) With the cell phone, there isn't any arrow to distract. Just heading and distance. This seems less prone to error.

Edited by dpbabcock
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Chuck, why are you using an adapter with your camera? The camera is USB, I'm sure - I've never heard of a camera with a serial connection. If you are trying to connect a USB device to a serial port on your computer, then you need a different device.

 

Mr. Babcock, I've been flying for 40 years, professionally, and I say once more, your heading is the direction you're moving, or at least facing, while bearing is the true (or magnetic) course to your destination. Your heading while flying may not be exactly the same as the course made good, but the bearing to the destination or station is always the direction to it, regardless of your heading or course made good. What you're depicting on your eTrex is the bearing.

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Chuck, why are you using an adapter with your camera? The camera is USB, I'm sure - I've never heard of a camera with a serial connection. If you are trying to connect a USB device to a serial port on your computer, then you need a different device.

 

Mr. Babcock, I've been flying for 40 years, professionally, and I say once more, your heading is the direction you're moving, or at least facing, while bearing is the true (or magnetic) course to your destination. Your heading while flying may not be exactly the same as the course made good, but the bearing to the destination or station is always the direction to it, regardless of your heading or course made good. What you're depicting on your eTrex is the bearing.

 

Well after doing a bit of research, I believe you are correct. I stand corrected. The common usage seems more in line with what you've said. I knew what I *meant* to say but it looks like I got it backwards from the purest definition of the terms that I could find in some on-line resources. Thanks for working with me on that. I like to get the details right. Programmers (geeks) are that way. I've got to change the "Heading" label on the screen to "Bearing" :drama: I was just sitting here working on the program and just got the "Over the Air" (OTA) GPX file download working and took a break to check up on my other on-line interests (including this forum) and I saw your reply.

 

Many times I've loaded up the waypoints I thought I needed before a caching session only to find out that I had forgotten some when I got in the field. Now if I have cell coverage I can just point the app to the GPX file URL on the web and suck them all into the waypoint list directly OTA. I'm getting truly spoiled by this wireless stuff, especially the Bluetooth. I wish the E-Trex had that capability. It always seems that the cable is not handy and it's a bit of a nusiance to hook up. It's SO nice to be able to load data just being NEAR the PC (like synching your appointments, addressbook etc.) Now I can load waypoints anywhere I have cell connectivity WITHOUT a PC right in the middle of the woods if I need to. I'm having way too much fun with this (g).

 

Anyway, you've done me a service by helping me get the terms on the program screen right. If I get this thing polished enough to market it, you'll get a free copy if you have a Java enabled cell phone or PDA that can run it. Just look me up and remind me of the offer (g).

 

Thanks again.

 

-dB

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Chuck, why are you using an adapter with your camera? The camera is USB, I'm sure - I've never heard of a camera with a serial connection. If you are trying to connect a USB device to a serial port on your computer, then you need a different device.

Camera was an old Kodak DC210 we bought around 1999 or 2000. It was serial only, and darn slow to transfer pictures too. I swear it ran at 1200 baud.

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A serial camera, huh? Well, the advantage of serial is that it's reliable, and works between any two devices, doesn't have to be a PC, host, or anything else. It's not fast, but it works.

 

dpbabcock, I connect my eTrex Legend to my PDA via bluetooth. PC-Mobile sells a bluetooth adapter, running on AA batteries, which can connect to any GPS, if you have the right cable. Making one with a 2.5mm plug on one end, and an eTrex connector on the other can be a PITA, but it's doable. Or you can buy one from PC-Mobile. I'm cheap, and had the parts already on hand, so I made my own. I also use the adapter in the car, to connect my old RS Digitraveler to the PDA or my laptop via bluetooth, using another cable. That GPS is wired in permanently, so I don't need to fiddle with the Legend - just turn on the adapter and I'm ready to go. I could make up a way to power it automatically from the car, but it hasn't seemed worth the effort yet.

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Chuck, why are you using an adapter with your camera? The camera is USB, I'm sure - I've never heard of a camera with a serial connection. If you are trying to connect a USB device to a serial port on your computer, then you need a different device.

 

 

My old Olympus D 340R is a serial (RS -232) connect camera also.....

 

Dale

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I had some problems with the Belkin USB-Serial adapter with some devices (Yaesu FT-8900R transceiver) but not with others (Yaesu VX-7R and FT-817ND transceivers), so I bought a PCMCIA-Serial adapter from Startech.com and it works extremely well. I had to update the driver to one they e-mailed me in order that my laptop PC would be compatible, but it works without any problems. Check them out for all sorts of interconnection devices.

 

Here is a link to their I/O products for desktop and laptop PC's:

 

Click Here.

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