Purple Project GPS Connectors

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Press release: ePlugs for Garmin eTrex and eMap are on their way.
The pledge for the ePlug is R100 for a pair.
We also have available the 12 way connectors for the Garmin OEM boards. We will be making up cable harnesses for them soon. This is the GPS25 units. Still amongst the smallest OEM GPS receivers on the market.
Also available are antennas for the handheld GPS's at prices much less than Garmins. Price of antennas is R380 including VAT and postage to anywhere in South Africa. Currently only have 5V antennas in stock for the older Garmin Handhelds. Connectors are BNC or MCX.
Prices available from Interface Products.

History

Once upon a time : Larry got frustrated with the price of the link and power cables that were available for his new Garmin GPS receiver. After some though he decided to make his own and there was an overrun of a few (hundred).

He offered to send these to interested parties for free. People heard about this and more people wanted them. Larry had to come up with a plan quick or there would be a lot of unhappy people. In exchange for a small sum of money Larry decided he would go to the effort of making more and sending them to all the people, this has prooved to be a success.

Anyway Larry tells the story better so I suggest you look at the pages of the Purple Project for a much more entertaining version.

These days it is all old hat and public knowledge on the Internet that one can get connectors for your Garmin Handheld GPS receiver (some models) via one of the many Pfranc's (over 35) from all corners of the globe.

This page is not in any way afilliated with Garmin. We wish to specifically acknowledge that many names or trade-marks used on this resource remain the property of their owners.

Information

The Purple Project connectors are for the newer Garmin handheld GPS receivers. The compatible GPS receivers includes the GPS12, GPSII+, GPS12XL, GPSIII and a few others that are no longer that popular. You can get hold of new handheld Garmin GPS receivers from Interface Products.

This connector is the round polarised connector with 4 pins that is used to communicate with, and supply power to the GPS receiver.

The GPS signals
The receivers all have the same pinouts and serial levels. The serial levels are apparently not quite RS-232 (though very compatible, only + - 5V swing), NMEA (-ve voltage), TTL (wrong polarity as well as -ve voltage) or RS-422 (not differential and -ve voltage). Now all of these with the exception of the TTL can be made to work with at most an additional resistor but RS-232 is the intended one and I have not heard of any compatibility problems with this so far.

The RS-232D specification does allow for relaxed output voltage excursions for just such battery portable equipment and the + - 5V is within those limits.

To make a Garmin - Garmin cable you take two connectors and wire the grounds together and the Tx-data of one to the Rx-data of the other and vice-versa.

The power supply connection shares the common ground wire and makes use of the 4th connection. The input voltage is not the same across the whole range of Garmin GPS models though. The reasons are many but there are basically two ranges of input voltage for the various models with some minor variation. I will list those I know for sure.

Low voltage models : 6 .. 8 V DC regulated
GPS12
GPS38
GPS40

High voltage models : 10 .. 24 V DC regulated
GPS12XL
GPS45
GPS45XL
GPSII
GPSII+
GPSIII
GPSIII+

Dunno, 12V is probably ok
GPS12CX
GPS12MAP
GPS48

I will add in the others when I have checked doccumentation and as I get information on others. As well as opening the limits slightly to cover the listed voltages and not my recollected conservative ones.

The Connector
The Purple Project connector is made up of 3/4 plastic components and held together with a small screw with all 4 contacts captive between two of the plastic parts. The cable exit is at right angles to the line of the contacts to allow for easy cable routing at the back of the GPS unit. The old connectors are not designed to, and do NOT, fit into the slot of a Garmin GPS12/38/40/45 mounting bracket without modification, to the bracket that is. New connectors do fit into the Garmin braket.

Assembly
Assembly of the connector is not difficult and takes a few moments of preparation, access to a soldering iron with a small bit and a steady hand.

You need to collect references of pinouts for the Garmin (see below) and your computer or other device you plan to attach to and then prepare your cable, the connector and solder the wires on, close the connector and terminate the other end.

Some people suggest using RTV (room temperature vulcanising) sealant or Hot-Melt glue to seal the top of the connector but this is not strictly required. Use of a short length of sleeving (heat shrink or Air-Shrink) over the cable exit finishes the job neatly.

Even if you do not plan to connect all the pins, leave them in the connector as they will be there when you need them.

If you are making a 12V (anything greater than 8V) power cable you should close the central hole in the plug with the small plastic plug supplied to prevent someone from plugging it into one of the units that cannot handle the higher external voltage. They have a plastic keying pin in the center of the socket to allow insertion of low voltage power cables only.

Ordering Information

For people in Southern Africa I can supply you with connectors with minimum postal delay and you can pay in South African Rands or US Dollars. The way it works is this, you send me E-Mail with the Subject line Pledge ZAR 70 or Pledge US$ 10 for a gPlug or alternately Pledge ZAR 100 or Pledge US$ 15 if wanting ePlugs for the new compactr Garmin units as suits you with your postal address and any other comments in the message. A contact phone number for our records is appreciated. I then send out 2 connectors to you in the mail. I usually send them out in 0 to 2 days via FastMail in South Africa and airmail into Africa. It takes about 1 to 5 days to get to the destination usually.

After receiving the connectors and finding them to meet your needs and expectations you then post cash, postal orders or cheque for the amount you pledged (or more or less as you feel the service and product warrant) back to me. Postal Orders and cheques in ZAR only, crossed and made out to Kalle Pihlajasaari. Cash via registered mail please. Send to the following address.

Kalle Pihlajasaari
P O Box 15775
DOORNFONTEIN
2028 South Africa

As we no longer supply made up cables we recommend Sarel.

My friend Sarel van der Walt makes up cables with modular plugs that allow for connecting to power and PCs and other Garmins.
He also has the local agency for a digital mapping software product called QuoVadis.

You can reach him at
Cell : (082) 888-8666
Fax : (012) 991-4623
+27 (12) 991-4623 (international)
e-Mail : sarel@africanstuff.co.za
Web site : Here

Want to become a Pfranc for uncharted teritories, check out the Purple Projects Pages.

File Archive

This is going to be a collection of files related to the Purple Project GPS connectors.
    Local files
  • connect.doc Packing sheet by Kalle Pihlajasaari (37kb)

    • Off site files

  • x.txt Coming Soon from Resurrect Roy (?kb)

Image Archive

This is going to be a collection of images related to the Purple Project GPS connectors.

Web site links

This is a list of links to websites with content that has some bearing on the topics at hand.

Do you have a link you would like to add here, if so send me mail.

Disclaimer or other Postscript.
Created 21 July 1997 © Kalle Pihlajasaari Last changed 23 August 2000.
http://www.ip.co.za/people/kalle/purple.htm Purple Project GPS Connectors kalle@ip.co.za