There is probably no harware item with more intricate diversity than
*connectors*. Yet, only the XLR has been discussed here (item 47). 
This item if primarily for help with finding/using connectors, lets
hear some amusing or horrendous connector stories too. 

50 responses total.

When I lived in England, I discovered that there were more than a dozen
ordinary household 2-conductor electrical "plugs": differing in
prong shape (flat or round), width/diameter, and spacing. In one home
I counted 14. Generally the bigger ones were for bigger currents
(and vica versa), but no one could explain the variety. I have the
same feeling of amazement and befuddlement over the variety of RF
connectors (UHF, BNC, F, N, SMA, MHV, SHV, C, HN, SC, SSMA, LC, 
TNC, SMC, SMB, SSMB, D, and BANANA (did I miss any?)). Then, there
are computer connectors......but I'll let this item loose, before
I ask about one I'd never seen before.

RCA, 1/4", Ampex, alligator, DIN, Amphenol, Molex, barrier ...

Are connectors a metaphor for human discursiveness? The variety of
connectors is mirrored in the variety of shampoos, cars, computers,
and practically everything else people use. Generating this variety
consumes an enormous overhead of repetition. On the other hand, 
functional variety, and competition, are both valuable and lead to
innovation. But I think the balance has gone too far when so many
essentially identical but incompatible "thingies" are produced by
society. 

ok, tyr connecting tri-ax with alligator clips ... or disk-drive
signals with phono plugs ....

        
        <G!>

Those would, at least, be adventurous.

Here is my particular connector question: my Garmin-40 GPS has a
computer interface and external power built-in connector, which is
a 0.53 in diam by 0.31 in deep cavity, with 4 D-Sub pins on a ca. 0.31
in diam circle (equally spaced), a key at 45 degrees, and a ca. 0.07 in
diam central plastic pin. I know the pinout (gnd, +6v power, RS-232
send and receive). What connector is this? (The Garmin power and data
plug for this is, of course, somewhat expensive.)

Hmm, kind of sounds like a varient of a DIN style connector from your
description. It's about the size of an IBM keyboard connector?
I'd have to get a look at it for sure. Is the plug smooth or are there 
threads?

I'd like to find or make the plug. The socket (with the pins) is
smooth. I have D-sub socket (female) "pins" (for DB connectors), so
I can easily connect wires to the four GPS pins, but I'd like to house
that setup. 

Hmmmm, well ... from my handy Woodchuck's Handbook, it sounds
very similar to an AMP, Series 1, CPC (circular plastic
connector)  with size 16 contacts, 4-position with built-in
pin and socket protection, positive ident locking, and
key-polarized.
  
But, hey, what do I know ...... <g>.
  
very popular for the aircaraft/computer/instrumentation
industries. 

Does yours have thread-assisted coupling or bayonet coupling?
  
And which wire size would it use, 18-16 AWG, or 22-28?
The contacts are different for the different wire size.
  

Hey! Do you have one? No coupling at all - it's just a cylindrical
cavity (i.e. hole) in the plastic body of the GPS. The pins are the
same size as in ordinary DB computer cable connectors. The D-Sub
female pins (sockets) are made to be crimped with a tool, and would
take 18 AWG wire, but all currents are very low (ca. 120 ma power).

Hmmm, if that's just a friction-fit connector, I "found" the
wrong one.
  
It could be a customized variant, as gregc noted, of a DIN plug.
  
Can you identify any mfgr markings on it? 

Its integral with the body of the GPS - not a separate fitting. What's
the prospect of building one? Cast the body out of (something?) with
the sockets inserted? I'd be a little concerned about casting it right
in the GPS, as I don't know what plastic it is and what might dissolve
it, but I could test castable polymers.

I think you'd be much better off trying to *buy* a connector, than
build your own. 2 suggestions: Have you tried contacting the manufacturer?
It seems to me that they just *might* have some idea about where to
get a connector. Or, take the unit to RS electronics on schoolcraft rd
in Livonia. If they don't have one in stock, they can probably order it.
They have a *huge* warehouse. They are a major electronics distributor,
of about the same size as companies like Newark and Hamilton-Avnet.

Yes, there are power and computer interface accessories from Garmin.
But, where is the adventure in that (and the money savings). I *know*
you make things sometimes, instead of buying them, Greg. (In addition,
no accessory information or dealers names came with the unit, and my
call to the company got an answering machine, and the information I
asked for hasn't come....so I'm day dreaming about rigging my own.)
(And I showed the unit around at the ARROW meeting, and had offers
of machining a plug for it - see? others are just as taken with these
little "trivial" challenges.)

Nothing wrong with that. You just hadn't made your intentions clear.
If your main goal is just to see if you can make your own connector,
well then, have at it. OTOH, if your main goal is to acquire the information
available on that plug in a timely and reliable manner, then you are
better off buying professionally made parts.

Another option would be to substitute a more commmon jack/plug for
the one that is in there. Being integral has its limits.

TS, the whole unit is "integral"! It is hermetically sealed with a dry
nitrogen interior atmosphere (because the unit is meant for use on deck
aboard boats, and *everything* gets soaked on boats). This inquiry has
been useful to me in other ways. It led to the comment that the connection
might be TTL and would need an interface to EIA-232. I'll put a scope on
it to see, but that might be enough to disabuse me of do-it-myself ;-! 

well, don't let that hermit out - 

TTL level is easy to convert to RS-232.  A single 16 pin chip, 4- 10uf
16v capacitors and some wire.  Using the 4 caps, it even has a charge
pump supply to generate the required RS-232 voltages.  One could build
the whole thing on a square inch of PC board space.  (I'm speaking of a
MAX-232 and like devices.)

I've heard of such. (I've heard of so much, but still know so little -
funny how that works.) I'll be back after I check levels, and see what
the Garmin accessory info is: both should add information 8-}.

One could even take a standard serial card and pull out the 1488 and
1489 (Or equiv.) line drivers.  They would be replaced with jumpers.
Then one wouldn't need to convert the TTL level signals from the GPS.

I scoped the in/out pins, to ground, and they are at ground potential
with no signal, with the Garmin on, *but not acquiring data* (i.e.,
indoors). Does that give any hint as to what kind of interface it is?
(I misremembered an earlier measurement which I thought showed a
potential.) I'm going to have to get the tech data.

It might also be current loop.  Why +6v ?  You ought to be able to ask
the Garmin people what the interface is.

The specs say +5 to +8 V for external power, but 4xAA are used for mobile.
I'll keep pursuing Garmin, but they haven't responded to my request
(taken on vice mail).

Now would be a good point for someone else with a CONNECTOR problem
or question to jump in. Next time I have more info, I'll post it in
the GPS item. 

I needed some flexible 4-wire shielded cable, so bought a "ST. KEYBOARD
CABLE" with 5-Pin DIN M-F connectors. I don't need the connectors, and
will be cutting them off the cable. They are molded onto the cable. Does
anyone want the connectors with, say, a foot of cable left on each?

hmmm, better not, I have a large enough collection - however if
no one needs them now .. they might be fodder for JCC.

Does anyone have a *crimper* for machined pins for Sub-D connectors,
of the type that are first crimped to the cable wires, and then inserted
into the holes in the Sub-D shell, to make DB-25 (etc) - that I could
borrow?

If they are open barrel connectors, I've got a tool. It won't work with
closed barrel connectors. Open barrel are the most common, they have
small flanges that are crimped over on the wire. Closed barrel are
more expensive and the better ones are ussually mil-spec. They are hollow
tubes on the end that the wire is inserted into. The tool then crimps from
4(or 6) directions at once and squeezes the tube.

If you're going to the JCC tomorrow Rane, I could bring it with me.

I like to crimp "closed barrel" pins (which is what "machined" pins" means).

Guess I'll solder those pins. NOW, does anyone know where I can get 
smallish quantities of a "liquid" two-component (resin and curer)
RTV rubber, for molding the connector I need?

Re #6-#17 (and others): I have made a connector to the Garmin GPS starting
with RS 274-001, removing its sockets and drilling out the holes and a
center-post hole; solding D-Sub sockets to the cable wires and inserting
the socket pins into the connector body and onto the GPS jack pins; and
expoxying the bases of the pins into the connector body while it was all
assembled (in summary...took a good part of the day 8-/). You can't afford
to have me make one for you ;->.

oops, havne't been here for a while --- about the resin and cure,
I'd try Purchase Radio first, and Rider's Hobby second.

Now, lets move on to the RF connector - an MCX. I finally found a
distributor for the MCX, but the catalog they sent me has no prices
(and no price list was sent). I see that there policy is, if you
have to ask the price, you can't afford it. An alternative is apparently
an SMB, if one files down the outside diameter. But the SMB is a
"crimp" cable connector (for small cable). So my question is, presuming
I can get the connector and cable to match - is there a good way to
crimp it without the $52 tool?

I bought an MCX connector. A person on .sci.geo.satellite-nav bought
six from the dealer, and offered 5 for sale. It is sure a teensy 
little thingy - very nicely made and gold plated. Now the problem is
connecting it to a cable (like RG 174 etc). Unless I can locate a
crimper, I guess its a solder job - under a binocular microscope.

I'm also 'back on' this project (a result of being semi-retired). I bought
an external powered GPS antenna (a cheaper one came available), but it
ends in a male BNC connector. I need to go to the MCX - need a short F-BNC
to M-MCX patch. I've put many a UHF connector on cable ends, but never a
BNC.  The ARRL handbook describes various clamp type BNC cable connectors,
but most on the market are crimp type. In-line females are also rare. RS
has only "twist on", and nothing for RG 174 cable. I *might* be able to
get crimp service from a colleague.  I would value any advice about the
choices. Can any of them be soldered instead of crimped, to make a good
connection ?  (It matters at 1575 MHz.)

I don't know much about crim-on connectors except that I don't have as
much trust in them as a soldered connection.  Purchase should have the
screw-together connectors you are looking for.  I've heard that the
crimp-on connectors have more of an impedance change at the connector
than the good screw-together type.  When using the crimp type, you
also need to use the crimp tool designed for the connector your using,
otherwise the impedancce bump will be even worse.  Go with a well
know barand name, like AMP.

Unfortuantely, Purchase did not have an inline female for RG174. I like
the idea of the clamp (screw-together) unit better, too. I might have to
buy one from AMP - Mouser, Digi-Key, and various 'surplus' sources don't
offer the female-clamp-RG174 connector.  (Pasternack has one for $6.75,
but a $100 min order).  Bother.....

How anout using a female to female barrel connector instead?

And put a male BNC on the end of the MCX-BNC patch? Could do, but I
want to minimize connectors. That would add another one. However, 
given the real world......that might be the economical solution.

- Backtalk version 1.3.30 - Copyright 1996-2006, Jan Wolter and Steve Weiss