Tripmate connector for APRS
I recently purchased a Tripmate GPS at discount and wanted to modify it to work with my APRS tracker, but without making any changes to the Tripmate unit itself. I had originally built my tracker with a slight variation of N1QKP's APRS / HAM RADIO Standard Connectors. So, basicly I was faced with building an adapter from the 9 pin D-sub on the Tripmate to the color coded RCA phono plugs for Power and Data. Using N9UUR's modification as a guide, I preceded to build a tripmate adapter into a 9 pin male d-sub connector. The following photos are linked to larger images (approx. 200 kb each) for more detailed viewing.
I used a 7805 regulator, 9 pin male d-sub, and metal d-sub case. In order to fit the 7805 into the d-sub case, I needed to shave down the sides of the mounting tab. In order to bend the contacts, I held them with a needlenose pliers right next to the plastic case to prevent from breaking the case. I cut the soldering cups from the unused pins 6,7,and 8 of the d-sub, to allow a little extra room for the 7805.
Next I drilled the metal d-sub case and attached the 7805 with a machine screw and nut. It is very important to determine the correct contacts on the 7805. On the one I used, looking at it from the front, heat sink to the back, mounting tab up, and solder legs down, the left contact is 12 v in, center is ground, and the right contact is 5 v out. If you have one with different pin outs you will need to adjust connections accordingly.
To prepare the d-sub connector solder as short a jumper as possible across pins 2 and 3. This will allow the Tripmate to hear it's own Astral string from data out pin 2 on data in pin 3. Solder another jumper across pins 9 and 4. This will tie in the DTR line pin 9 with the 5 volts power on pin 4 to allow the Tripmate to self-start. Also solder a short hook up wire to pin 4. Finally solder an insulated hook up wire to pin 5 ground.
Place the d-sub into the section of the d-sub case with the 7805 mounted to it. Connect the wire from pin 4 of the d-sub to the 5 v out pin of the 7805. Connect another insulated wire to the ground pin of the 7805.
I prepared my power and data connectors by using shielded single conductor audio cable approximately 9 inches long. The black phono plug is for power. The center wire is connected to the center pin and the shield is connected to the outer. The red phono jack is for data with the center wire connected to the center pin and the shield connected to the outside. I stripped the jacket from the other end of the wires approximately an inch and a half, clamped them together with the strain relief for the d-sub, and twisted the shields together.
I placed the cable assembly into the partially assembled d-sub by aligning the strain relief into its proper position. The data wire is cut to length, stripped and soldered to pin 2. The positive power wire is cut to length, stripped and soldered to the 12 volt input pin of the 7805. I then wrapped the two ground jumpers around the cable shields and soldered them all together, then cut off as much excess as possible.
I completed the adapter by connecting the other side of the d-sub case, and added hex nuts to the mounting screws. I checked and tested all connections to be certain there were no shorts and that all connections were correct. I applied 12 volts to the power cable and tested for 5 volts on pins 4 and 9.
The final step was to open the battery compartment of the Tripmate, unplug the battery cable and place a computer type shorting block on the two pins towards the center of the unit.
Created by B.E.B.
Copyright © 1999.
All rights reserved.
Revised: January 1, 1999
I used a 7805 regulator, 9 pin male d-sub, and metal d-sub case. In order to fit the 7805 into the d-sub case, I needed to shave down the sides of the mounting tab. In order to bend the contacts, I held them with a needlenose pliers right next to the plastic case to prevent from breaking the case. I cut the soldering cups from the unused pins 6,7,and 8 of the d-sub, to allow a little extra room for the 7805. 
Next I drilled the metal d-sub case and attached the 7805 with a machine screw and nut. It is very important to determine the correct contacts on the 7805. On the one I used, looking at it from the front, heat sink to the back, mounting tab up, and solder legs down, the left contact is 12 v in, center is ground, and the right contact is 5 v out. If you have one with different pin outs you will need to adjust connections accordingly. 
To prepare the d-sub connector solder as short a jumper as possible across pins 2 and 3. This will allow the Tripmate to hear it's own Astral string from data out pin 2 on data in pin 3. Solder another jumper across pins 9 and 4. This will tie in the DTR line pin 9 with the 5 volts power on pin 4 to allow the Tripmate to self-start. Also solder a short hook up wire to pin 4. Finally solder an insulated hook up wire to pin 5 ground. 
Place the d-sub into the section of the d-sub case with the 7805 mounted to it. Connect the wire from pin 4 of the d-sub to the 5 v out pin of the 7805. Connect another insulated wire to the ground pin of the 7805. 
I prepared my power and data connectors by using shielded single conductor audio cable approximately 9 inches long. The black phono plug is for power. The center wire is connected to the center pin and the shield is connected to the outer. The red phono jack is for data with the center wire connected to the center pin and the shield connected to the outside. I stripped the jacket from the other end of the wires approximately an inch and a half, clamped them together with the strain relief for the d-sub, and twisted the shields together. 
I placed the cable assembly into the partially assembled d-sub by aligning the strain relief into its proper position. The data wire is cut to length, stripped and soldered to pin 2. The positive power wire is cut to length, stripped and soldered to the 12 volt input pin of the 7805. I then wrapped the two ground jumpers around the cable shields and soldered them all together, then cut off as much excess as possible. 
I completed the adapter by connecting the other side of the d-sub case, and added hex nuts to the mounting screws. I checked and tested all connections to be certain there were no shorts and that all connections were correct. I applied 12 volts to the power cable and tested for 5 volts on pins 4 and 9.