How to make a Macintosh/Garmin cable

(For new Macintosh computers a Bluetooth GPS is the best solution!)

Brought to you by Clover Technology AB in Sweden

With this cable you can connect a hand held Garmin GPS to the printer or modem port of your Macintosh. The same cable also works with the Newton PDA.

What you need:

The kind of cable you choose is not critical. Solder the tricky part first (the DIN connector).
You only use pins 3, 4 and 5.

Now to the Garmin end. Identify the pins in you Garmin - pull out the rubber protection on your GPS and look at the connector. You have a plastic ridge at 11 o´clock, we use this as reference. Clock-wise from this you have Data-in (at 12 o´clock) - to pin 3 of the DIN-8, ground (at 3 o´clock) - to pin 4 and Data-out (at 6 o´clock) - to pin 5.

If you also want to connect power this is OK as long as you use the right voltage (some Garmins should never be connected to more than 8 Volts - read your manual). Connect a power (+) to the remaining pin and ground to the same ground as the data uses.


Apple Macintosh and Newton DIN-8 connector:

 

 1 
2
 
 
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 ° 
3
 
4
 
5
°
 
°
 
°
6
 
7
 
8
°
 
°
 
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Miniature DIN-8 jack

Pin

RS-422 signal name

Direction

Remarks

1

Handshake output DTR

HSKo

Voltage from Mac

2

Handshake input CTS

HSKi

Input to Mac

3

Transmit data -

TxD-

Voltage from Mac

to Data-in on Garmin

4

Frame ground

GND

to ground (-) on Garmin

5

Receive data -

RxD-

Input to Mac

to Data-out on Garmin

6

Transmit data +

TxD+

Voltage from Mac

7

Gen. Purpose Input or no connection

GPi

Input to Mac

8

Receive data +

RxD+

Input to Mac

in rare cases this has to be connected to pin 4