[aprssig] Re: APRS Standard Connectors?

Robert Bruninga bruninga at usna.edu
Wed Nov 30 08:09:27 CST 2005

20 years ago we were all using the TAPR-2  
5 pin DIN connector as the audio standard.
I made all my patch panels match it.

But nothing beats the "DB" series for solderabiilty.
So I like K6DGB's suggestion below.  The KPC-3 DB-9 for
audio and the PC (AT) serial port DB-9 series for
GPS interfaces.  I like the addition of +5 and +12
on separate pins!

TNC or Interface device (not radio end):
DB series 9 pin Female on chassis, Male
on cable.

   1      TX Audio
   2       (XCD input)
   3      PTT
   4      (ctrl-B or analog input)
   5      RX audio
   6      GROUND
   7      Power Input
   8     (ctrl A or analog input)
   9      GROUND

Many GPS devices expect to be plugged into
a PC, so they have a DB-9 series female on
the end of their cables.  So the standard APRS
GPS connector could be:

   1     (DCD)
   2     Serial GPS data to PC
   3     Serial data to GPS
   4     Power 12 volts
   5     GROUND
   6     (DSR)
   7     (RTS) Suggested 5 Volts Power?
   8     (CTS) 
   9     (???)

Notice that Chris suggested pin 8 for 5V power,
but since the PC is the DTE and the GPS plugged
into the serial port is the DCE, then I think the
PC should output the 5 volts on pin 7 which is
an output from the PC and not pin 8 which is
normally an input to the PC.  Did I get that right?

>>> cak at dimebank.com 11/30/05 12:29 AM >>>
Standard connectors? To what? From what?

There doesn't seem to be any hope of a standard connector set at the
radio end; I've given up on that. When I modify an old radio to 
bring connections out, I use the Kantronics DB-9 'standard'. 
That's very convenient because the OpenTracker/TinyTrak world
has adopted it. Put the cap/resistor network for your HT's PTT in
the DB-9 shell so you can eventually connect another radio to
the device without having to restore the missing resistor.

At the GPS end, I use a DB9 again. The OT/TT folks put +12V on pin
4.  I needed +5, didn't want the chance of misconnecting and didn't
want to count on putting a regulator in the device's shell, so I
put +5V on pin 8. I declare that the new APRS standard. :-) 

For random power connections, I use PowerPoles. But Anderson doesn't
really supply a very good solution for chassis mounting them, which
still boggles my mind. (You can get pairs, or quads, but a single
connection requires a whole lot of fiddling to do well with the
little retainer plates.) Not to mention that they're not particularly
robust or dustproof. I liked the Molex 'standard' power connector

The coaxial power connectors are fairly horrible if you need 
more than 1A; some of them are rated at 0.5A. That's not
very much power (not even enough to transmit 5W). Someone already
mentioned the problem with shorting during connect/disconnect.

The great thing about standards is that there are so many to 
choose from.

73 de chris K6DBG

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