How to assemble our "pPlug" connector, and make a cable.
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  1. You can burn up your GPS with the power cable you make with my Plug.   Be extra careful if you have a low voltage model, the ones with 5 pin plugs. My connector lets you connect to the 5 pin models. The 5 pin models 8 volts max! The 4 pin models can take 32 volts and some even 40 volts.
    If you make a cable that can supply more than 8 volts (like a cigarette lighter) then make it into a 4 pin plug by inserting the little "plug plug" I provide with the kit. (Get it? A plug for a plug is a "plug plug".) Be responsible - don't smoke a Garmin. (BTW, The Rx data line is OK with COM port voltages (+/-12V), no problem). (BTBTW, as of 2011 (14 years and 750,000 plugs later) I have not received one report of anyone burning up a GPS - good going guys!

  2. Power cable for your car must have a fuse, most cigarette lighter sockets have a built-in fuse. Don't smoke your car.

  3. Address RF. You can add a ferrite bead to reduce RF (Radio Frequency) interference inadvertently generated by computing devices. The FCC Compliance Statement in your Garmin manual explains your responsibility.

    Garmin is a great company. buy GRMN stock. .

  4. Here









    Dave, Pfranc of Wisconsin, created this drawing for us. And Markku, Pfranc of Finland, has recently brought it up to date.

    Assembly diagram

    1) Assemble the connector as shown above except leave the cap off.

    2) Solder the wires to the pins. Do not heat a pin too long or the plastic will melt. It is best to pre-tin the pins and wires with flux core solder then "re-flow" quickly. Ideally the iron tip is about the width of a pin, tinned (shiny clean), and around 650degF.

    3) Lastly, install the cap.

    Please PLUG center hole if not needed!

    I added the center hole so the connector would fit Garmin units other than my GPS-45. What a nice guy I am? Later I learned that the 5 pin Garmin units require regulated voltage (less than 8 volts), unlike my 45. That's why Garmin added the 5th center pin! To protect it from unregulated power cables. So if you build a unregulated power cable, plug the hole so your cable cannot someday accidentally cook a 5 pin Garmin! I even added a plastic "plug plug" (a plug for a plug:-) part to the mold to make it real easy.
    Lets make a PC cable ... for Mac
    see below.
    The pin-out for the 45 is found in Appendix F ( page 55 ) of the GPS 45 Owner's Manual & Reference, and Dr. V's great graphic below. Notice the view (in your manual) is the "cable view" as if looking at the connector on the cable from ... um, which direction?... very confusing. Not a problem with Dr. T.V.'s super diagram, take note Garmin! (... UPDATE: Garmin has improved with every new model! Congrats Garmin! ) Notice the position of the key-way notch. Notice if you get power and ground backwards you will make your new GPS all black inside! (... more updates: I've put + and - and R and T right in the mold so you can check it easy ... Congrats to Me! )

    Use a red wire for Power(+) and a black wire for Ground(-). When your finished cable is plugged in (with no power attached!!!), check that the red wire is on the same side of your GPS-45 as the antenna. OTHER GPS models, I do not know! You have to know so check it out!

    I understand that Power can be from +7VDC to +32VDC (way cool)...but not the GPS-12 or GPS-38! (and maybe others) ...which needs 5VDC to 8VDC max.... read ... do not exceed EIGHT volts! Did you know that a car's battery can be 18VDC or more? If you have one of the "low voltage" GPS's, see a regulated power supply by John Mills that is adjustable and has extra protections added... thanks John. Notice that John answered the question about the best voltage setting, ... it's 7.3 Volts!

    To connect to a PC just attach a DB-9 female connector to your cable: Pin 3 is "TxD" which means Transmit Data - aka "data-out-of-the-PC" which you want to hook up to "DATA IN" of the Garmin. Pin 2 is "input to the PC" labeled "RxD" for "Receive Data" - which you want to hook up to "DATA OUT" of the Garmin, and lastly pin 5 is ground which you want to hook up to the GROUND pin of the Garmin.

    Several people have have said a dead mouse tail makes a great cable.

    The Dr. T.V. diagram.

    Check this out here .... Man, is this gorgeous or what? Dr. Thomas Vonesch of Switzerland did this in 1996 for us, before Garmin had a web site! 14 years later Garmin moved to Switzerland!

    If you need that round connector above... Click here. Now about the drawing. "Gruezi" ... (means "Hi" in Swiss-German) Dr. T.V. made this and e-mailed it to me 17JUL96. (IBM stock was about $12 per share, Garmin about $7) This drawing is so great that countless people around the world copied it into countless websites and documents.

    Update: 12/2006 (10 years after writing the above), FREE? We love free. Plugs-for-a-pledge. Free help, free advice. IBM is pushing $100/share again, (after splitting 2:1 twice!), and did you notice Dr. T.V.s email address? Philips? Did you know Philips purchased Navteq many years ago and has invested hundreds of $millions developing the database? And now every GPS manufacutre wants/needs it? And Navteq has gone public, (NVT), and has traded from the $20's to the $50's. I think it will skyrocket like IBM, GRMN, and Google has since I first started this page here! Google these three words: [ Garmin Navteq stock ]. Hey, we not only send you plugs and help you make cables - we also help you get rich too! How about that? UPDATE: 5/2011, ... Garmin went to $120 then back down to $14 and I lost all my lifes savings - oh well, IBM is $170, TomTom bought Navteq. We went from sending 200 plugs a day to 2 plugs a month. What a trip.

    "You want POWER and DATA?" (me too:-) No problem.  Just do it.  The ground pin on the GPS is used for both power and data.  It is no problem for the GPS, power supply, and computer to share the same ground.  Matter of fact, it's a good thing!

    POWER from USB? Maybe. It's only 5 V but you can take 500mA per device

    The Mark Zimmerman Power/Data cable. 11/98

    More great information!  Our Pfranc in New Jersey USA is getting power from his laptop keyboard port!   It's only 5 volts so no regulator is needed for those Garmins that can't handle over 8 volts.  (Note: You may need to remove your batteries else the 5 volt supply could drain them.  If you know more about this please contact me.) Zim created some awesome drawings and wrote up a great "how-to" page. How to build a Better Garmin Cable for your laptop PC.   I am once again amazed.  Zim is a professional computer graphics artist, and writes good too!  He did all this work just to help you make a cable!  I am amazed that all these great people have done all this great work ... not for me, ... for you!   Remember when you honor your pledge that the money you send is not just for my little plastic connector but for our great Pfranc service and all this great information.   To honor your pledge is to honor us, our system, our efforts, and because it confirms our theory that most people are cool, honoring your pledge actually goes full circle and ends up honoring you! And pushes us to continue - so to earn and honor your honor. (i could go on and on - um, actually, that's the idea and point I guess... us going on and on.)

    A Garmin to Garmin cable.
    Think of all the cool things you can do with this cable. Copy all your data to a friends GPS right in the field! To make one, get 2 of my connectors and wire In to Out and Out to In and Ground to Ground. Now, that was easy, and thanks to us Pfrancs you save a bunch of money and get the parts fast and easy.

    Macintosh? We didn't forget the Mac! Thanks to Pfranc Christer in Sweden! Check it out here: Clove Technology home page. Not only does he tell you how to make a cable for your Mac, he will send you software too!

    Here is a great website with a page about how to assemble our pPlug with neat photos and all: WeetHet

    Please send any comments, help with links, facts, words, spelling, syntax, format, presentation, etc... (even if a comma is out of place).... E-mail to: Click here .... thanks!

    IPO: 2/96, last update: 10/99 ... Ideas and Help editing thanks to: Dr.T.V., Larry C., Russell Inman, Dave Sorensin (Pfranc of WI), Steve Hodgson, Robert Inouye, Nick Moore (Pfranc of AL), Martyn Johnson, Martin Jaunzemis, Mark Zimmerman (Pfranc of NJ), Markku Tamminen (Pfranc of Finland), José Ramos (Pfranc of Portugal), Dr. Antonio Rodríguez Franco (Pfranc of Spain), John Mills (, and many others.

    Countless hits since 17Feb97. This WAS our most "hit" page, but now, almost 10 years later, Nov 2005, it's "viewed" about 1800 times per month and is 0.7 percent (yes less than one percent) of the page views at Our number one most viewed page this month is the USB-serial page at over 22,000 per month, which is still only 8 percent. Wow, look at that, averages 3000 "visitors" and 8000 "page views" PER DAY!

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