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 °° 3 4 5 ° ° ° 6 7 8 ° ° °
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 |