Tripmate and KPC-3 Interfacing

Subject:     [APRSSIG:8268] Tripmate->KPC-3 Details
Sent:        1/6/97 12:33 PM
Received:    1/6/97 1:51 PM
From:        Randy Hammock, hammock@wired.jpl.nasa.gov
Reply-To:    aprssig@tapr.org
To:          aprssig@tapr.org

As promised, here are the details.

PARTS LIST
----------
9-pin male D-connector
9-pin shielded hood
25-pin male D-connector
25-pin shielded hood
6 inches 4-conductor cable (3-conductor w/ shield will work)
LM340T-5 +5v 3-terminal regulator
33mfd 16v tant cap
.1 mfd 35v ceraminc disc cap
1/4" #6-32 bolt, lock washer and nut

ASSEMBLY
--------
The +5v regulator was mounted inside the hood of the 25-pin connector hood. It was placed in the area where the strain relief goes. It does not impede the placement of the strain relief at all. I did use heat-sink compound on the mount as it does get fairly warm. This allows the hood to act as a heat sink. A fully metal hood would probably be better; however, the metalized plastic hood seems to work just fine.

I cut the leads of the regulator off at the point where they become wide. I cut the leads of the tantalum capacitor to be about 1/8" and soldered it directly to pins 2 and 3 of the regulator (pin 2 being ground and pin 3 being the +5 out). The .1 mfd disc was soldered to the same pins, too. I then soldered a 2" lead to the regulator pin 1 and another to pin 2.

The lead from the regulator pin 1 should be connected to the pin 25 of the 25-pin connector. The lead from regulator pin 2 should be connected to pin 7 of the 25-pin connector.

9-Pin Connector

I used a 4-conductor ribbon cable for the assembly. Pins 2 and 3 (DATA) were jumpered together and the green wire connected to that point. The white wire was connected to pin 4 (DSR), the black wire to pin 5 (GND) and the red wire connected to pin 9 (PWR).

25-pin Connector

The green wire was connected to pin 2, the white wire connected to pin 6, the black wire connected to pin 7. The red wire was connected to the regulator pin 3.

  9-pin                                       25-pin

   2--+
      +-----------------------------------------2
   3--+

   4--------------------------------------------6

   5------------------------+-------------------7
                        .1  |
   9-----------------+--||--+    +--------------25
                     |  33  |    |
                     +--||--+    |
                     | +    |    |
                     +----+ + +--+
                          | | |
                         +-----+
                         |3 2 1|
                         |     |
                         +-----+
                          | O |
                          +---+

Earlier, I mentioned using wire wrap to make the jumper inside the Tripmate as a way of getting power to the unit; however, I was able to use a jumper pin like those used on computer boards to make the jumper connection. This may not work for all types of jumpers due to the small size of the pins in the connector.

Don't forget to added the 4.7K resistor in the KPC-3 to assert DTR and the jumpers necessary to supply power to pin-25 of the data connector.

Enjoy. --

Randy Hammock        KC6HUR
rhammock@loop.com