We have frequent need (many times each week) to match devices to
"suitable" wall-warts/bricks. *I* do this with a dial caliber
and drill bits -- and a bit of math.

I need a scheme where "less skilled" (e.g., developmentally disabled)
folks can do this *reliably*. Even if I have to spot-check their results.

I'm thinking of just buying one of every connector and mate, labeling
them, putting them on a "key ring" and then just having folks fumble
around until they think they've found suitable mates.

The downside is that there are cases where a connection may *appear*
to "fit" but isn't truly appropriate. E.g., ID is a bit oversized
(or undersized, depending on your point of view).

Is there a better way?

Are there any other *mechanical fitting* issues that I may have
overlooked (obviously, there are electrical issues)?

Does such a prebuilt "kit" exist (nicely packaged, etc.) so I
can just buy a couple and save myself the hassle of making them?

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

On 6/15/2025 1:50 PM, Don Y wrote:

Is there a better way?

Cancel that. A colleague has something in the mail to me, already!

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

On 16/06/2025 11:28 am, Don Y wrote:

On 6/15/2025 1:50 PM, Don Y wrote:

Is there a better way?

Cancel that.  A colleague has something in the mail to me, already!

Let us know if it is any good. It is a problem that I have too.

I somewhat distrust that type of connector in general, unless both parts
come from the same manufacturer - some of them have a slit inner pin
that is slightly springy/compliant and would be appropriate to fit in a
solid tube in the other part, whereas others have a solid pin and some
of the sockets have a bifurcated springy inner contact. Where there is a
solid pin fitting in a solid tube, it seems they only work because there
is a sideways force on the whole thing from the asymmetrical outer
contact. Seems dodgy.

I've also come across the belief amongst the general public that it's ok
to plug in any of these barrel connectors as long as they fit,
presumably because that's mostly true of USB and so on. So they fry
their modem that wants 12VDC by plugging in a 15VAC adapter or whatever.

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

On Sun, 15 Jun 2025 13:50:46 -0700, Don Y
<[email protected]d> wrote:

We have frequent need (many times each week) to match devices to
"suitable" wall-warts/bricks. *I* do this with a dial caliber
and drill bits -- and a bit of math.

I need a scheme where "less skilled" (e.g., developmentally disabled)
folks can do this *reliably*. Even if I have to spot-check their results.

I'm thinking of just buying one of every connector and mate, labeling
them, putting them on a "key ring" and then just having folks fumble
around until they think they've found suitable mates.

The downside is that there are cases where a connection may *appear*
to "fit" but isn't truly appropriate. E.g., ID is a bit oversized
(or undersized, depending on your point of view).

Is there a better way?

Are there any other *mechanical fitting* issues that I may have
overlooked (obviously, there are electrical issues)?

Does such a prebuilt "kit" exist (nicely packaged, etc.) so I
can just buy a couple and save myself the hassle of making them?

The barrel connector situation is a nightmare. It doesn't help that
products come with unmarked warts with random voltages and powers and connectors.

There should be two power sources, USBc and PoE.

We need more cheap surface-mount modules that pick off and isolate
power for us. We use a Silvertel module in our PoE gadgets. It's not
cheap.

People are starting to put magnetic isolators on monolithic ICs, which
is progress in the right direction, even if most are not very good
yet.

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

On 6/16/2025 6:17 AM, John R Walliker wrote:

Power supplies for POE+ switches often use the same connector type but deliver about 52V at a few amps.

Yup. I have some midspan injectors that use a nominal 48VDC "brick".

The physical size of the barrel connector means -- nothing! <frown>

[OTOH, there are also amusing "smoke liberating" variations in what
folks will *call* PoE!]

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

On 6/16/2025 3:47 AM, Chris Jones wrote:

On 16/06/2025 11:28 am, Don Y wrote:

On 6/15/2025 1:50 PM, Don Y wrote:

Is there a better way?

Cancel that.  A colleague has something in the mail to me, already!

Let us know if it is any good. It is a problem that I have too.

What I do is label (pTouch labeller) every wall-wart/brick with the
identity of the device that it is intended to power. Often, this
may not be an intuitive label (e.g., "three device USB3 dock")
but, rather, some other more specific identifier (e.g., "KA-1772-P4").

While this can be frustrating to resolve ("What the hell is a KA-1772-P4?"),
it is guaranteed to be explicit and unique. (imagine having two different "three device USB3 docks"!)

[pTouch labeller sees more use than any other bit of kit, here! Each
networked device is so labelled with its network name, "root" account
name, password, magic keys recognized at boot; external disk
enclosures are labeled witht he number and size of the media within;
NASs with network names as well as media sizes; wall-warts/bricks;
etc. Plus, any items stored in unexpected/opaque containers
("dowel centers", "3mm M3-0.5 nickel 100°", "8P8C dust covers", etc.)]

In the past, I've used the "adapter connectors" from a universal power
pack as go/nogo gauges to identify the appropriate mating connector
(works for selecting the female plug but not the male receptacle).

But, this approach requires care in keeping track of the little
"adapter connectors" AND having a cheat-sheet to identify them
specifically (ID & OD). It's not the sort of thing these people are
likely able to make effective use of -- for more than a day! <frown>
(they'll be misplaced, damaged, etc.)

I somewhat distrust that type of connector in general, unless both parts come from the same manufacturer - some of them have a slit inner pin that is slightly springy/compliant and would be appropriate to fit in a solid tube in the other part, whereas others have a solid pin and some of the sockets have a
bifurcated springy inner contact. Where there is a solid pin fitting in a solid
tube, it seems they only work because there is a sideways force on the whole thing from the asymmetrical outer contact. Seems dodgy.

Yes. But, in our case, we're trying to rescue devices that still have useful life -- if we could only find the appropriate "power pack". Or, fabricate
one (I recently cobbled together a power pack for an electric piano that
would, otherwise, have been in the tip).

So, we're stuck with the choice made by the manufacturer and just need
to locate/fabricate something equivalent.

I've also come across the belief amongst the general public that it's ok to plug in any of these barrel connectors as long as they fit, presumably because
that's mostly true of USB and so on. So they fry their modem that wants 12VDC by plugging in a 15VAC adapter or whatever.

LaCie uses a 4 pin power connector (12, 5, GND, GND). It is so unique that
one is immediately tempted to use any power pack that bears such a connector.

However, other folks use the exact same power connector but pinned differently! And, pinouts aren't incompatible enough to just short out the power pack; instead, they fry the device being powered!

[I've adopted the policy of banning any device that uses such a power connector!]

[[I've also seen devices use a PS2 "keyboard" connector for power 12/5/GND. Really? Talk about a flimsy choice compounded by the possibilities of
frying a PC/keyboard!!]]

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

On 6/16/2025 8:59 AM, legg wrote:

They're not infinitely variable.

No, but there are a score or more different configurations
(neglecting length variations). And, many of them are
"close enough" that you can get the wrong plug to mate
and still not make electrical contact.

[And, the mechanical aspects still won't address V, A,
polarity, AC/DC, etc.]

Some info on the web wikimedia barrel connectors.

Here's a spreadsheet with ID, OD and center pin diameters,
along with mfr ident and typical use (user beware):

https://ve3ute.ca/query/IEC_EIJ_DIN_Barrel_Connector.zip

Center-pin equipped parts expect resistively programmed
info for correct function a la USB-C. Some expect to be output-voltage-adjusted by the same means.

I thought the "three-pin" variants talked to an I2C-sortof
device *in* the brick to identify the actual device?

Note that current ratings assume correct mating and may
not be guaranteed by various mfrs or vendors.

Labelling the installed connector can be useful if your
memory doesn't serve you well.

Once you have the mating wall-wart/brick, you typically
care little about the actual connector being used.
It's not like you're going to plug something ELSE into
that port.

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

On Sun, 15 Jun 2025 13:50:46 -0700, Don Y
<[email protected]d> wrote:

We have frequent need (many times each week) to match devices to
"suitable" wall-warts/bricks. *I* do this with a dial caliber
and drill bits -- and a bit of math.

I need a scheme where "less skilled" (e.g., developmentally disabled)
folks can do this *reliably*. Even if I have to spot-check their results.

I'm thinking of just buying one of every connector and mate, labeling
them, putting them on a "key ring" and then just having folks fumble
around until they think they've found suitable mates.

The downside is that there are cases where a connection may *appear*
to "fit" but isn't truly appropriate. E.g., ID is a bit oversized
(or undersized, depending on your point of view).

Is there a better way?

Are there any other *mechanical fitting* issues that I may have
overlooked (obviously, there are electrical issues)?

Does such a prebuilt "kit" exist (nicely packaged, etc.) so I
can just buy a couple and save myself the hassle of making them?

They're not infinitely variable.

Some info on the web wikimedia barrel connectors.

Here's a spreadsheet with ID, OD and center pin diameters,
along with mfr ident and typical use (user beware):

https://ve3ute.ca/query/IEC_EIJ_DIN_Barrel_Connector.zip

Center-pin equipped parts expect resistively programmed
info for correct function a la USB-C. Some expect to be
output-voltage-adjusted by the same means.

Note that current ratings assume correct mating and may
not be guaranteed by various mfrs or vendors.

Labelling the installed connector can be useful if your
memory doesn't serve you well.

RL

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

On 6/16/2025 9:35 AM, Don Y wrote:

[pTouch labeller sees more use than any other bit of kit, here!

I'm reminded of a pair of lists that was making the rounds a decade or
two ago; "Best and worst gifts for a Guy". Number one on the "Best"
list was a label maker, and the reason given was the fact that
absolutely everything on the premises would be labeled. Number one on
the "Worst" list was a chainsaw, and the reason given was "see label maker."

--
I'm part of the vast libertarian conspiracy to take over the world and
leave everyone alone.

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

On 6/16/25 9:15 AM, Don Y wrote:

On 6/16/2025 8:59 AM, legg wrote:

They're not infinitely variable.

No, but there are a score or more different configurations
(neglecting length variations).  And, many of them are
"close enough" that you can get the wrong plug to mate
and still not make electrical contact.

[And, the mechanical aspects still won't address V, A,
polarity, AC/DC, etc.]

Some info on the web wikimedia barrel connectors.

Here's a spreadsheet with ID, OD and center pin diameters,
along with mfr ident and typical use (user beware):

https://ve3ute.ca/query/IEC_EIJ_DIN_Barrel_Connector.zip

Center-pin equipped parts expect resistively programmed
info for correct function a la USB-C. Some expect to be
output-voltage-adjusted by the same means.

I thought the "three-pin" variants talked to an I2C-sortof
device *in* the brick to identify the actual device?

Some Dell notebook power supplies have used that approach.

The barrel consists of two concentric cyclinders with the outer being
the negative connection and the inner one being the positive supply. The
pin directly connects to a OneWire Dallas Semi/Maxim memory that has the
power supply ID.

The computer can then interrogate the power supply to determine current capability and that it is a genuine Dell supply.

My first exposure to one resulted in me destroying the supply!

There was no protection for the memory device and I accidentally shorted
the centre pin to the inner barrel when attempting to measure the
voltage output.

The 19V from the supply destroyed the OneWire memory. Whenever the PSU
was plugged into the computer it would not identify it as a Dell supply
and would not charge the battery and would only run at reduced speed.

It is not obvious that the outer barrel and inner barrel are not the
same connection.

Be careful with Dell supplies. Modern ones may be different this is from
~15 years ago

Note that current ratings assume correct mating and may
not be guaranteed by various mfrs or vendors.

Labelling the installed connector can be useful if your
memory doesn't serve you well.

Once you have the mating wall-wart/brick, you typically
care little about the actual connector being used.
It's not like you're going to plug something ELSE into
that port.

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

On 6/16/2025 12:07 PM, KevinJ93 wrote:

Some Dell notebook power supplies have used that approach.
...
Be careful with Dell supplies. Modern ones may be different this is from
~15 years ago

They still do this.

Interestingly, Dell and HP use compatible "Big Barrel" and "Small
barrel" power connectors. The voltage and polarity are the same. A
Dell adapter will work just fine on an HP laptop, because the HP does
not use the third pin to identify the adapter. However a Dell laptop
will complain about an HP adapter because it cannot read any identifier
on the third pin.

--
I'm part of the vast libertarian conspiracy to take over the world and
leave everyone alone.

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

On 6/16/2025 10:07 AM, KevinJ93 wrote:

Some Dell notebook power supplies have used that approach.

The barrel consists of two concentric cyclinders with the outer being the negative connection and the inner one being the positive supply. The pin directly connects to a OneWire Dallas Semi/Maxim memory that has the power supply ID.

The computer can then interrogate the power supply to determine current capability and that it is a genuine Dell supply.

My first exposure to one resulted in me destroying the supply!

There was no protection for the memory device and I accidentally shorted the centre pin to the inner barrel when attempting to measure the voltage output.

The 19V from the supply destroyed the OneWire memory. Whenever the PSU was plugged into the computer it would not identify it as a Dell supply and would not charge the battery and would only run at reduced speed.

It is not obvious that the outer barrel and inner barrel are not the same connection.

Be careful with Dell supplies. Modern ones may be different this is from ~15 years ago

Dell "desktop" supplies have similar quirks -- "wrong" pinouts, etc.

Most of the machines that I run have very *specific* power supplies;
nothing else will mechanically fit. This still leaves me at the
mercy of the vendor having a different (mechanically compatible) supply
for one model than another.

I pull compatible supplies, label them and toss them in a "parts box"
labeled with appropriate device's name. (Repairing power supplies is
just not a good use of my time; easier to just horde spares!)

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

Don Y <[email protected]d> wrote:

We have frequent need (many times each week) to match devices to
"suitable" wall-warts/bricks. *I* do this with a dial caliber
and drill bits -- and a bit of math.

I need a scheme where "less skilled" (e.g., developmentally disabled)
folks can do this *reliably*. Even if I have to spot-check their results.

I'm thinking of just buying one of every connector and mate, labeling
them, putting them on a "key ring" and then just having folks fumble
around until they think they've found suitable mates.

The downside is that there are cases where a connection may *appear*
to "fit" but isn't truly appropriate. E.g., ID is a bit oversized
(or undersized, depending on your point of view).

Is there a better way?

Are there any other *mechanical fitting* issues that I may have
overlooked (obviously, there are electrical issues)?

The trouble with 'just try it' is that the 'trial' sockets can wear over
time. eg if you insist on putting a 6mm OD plug into a 5.5mm OD socket,
it might go but bend the spring contact. Eventually the 5.5mm OD plugs will feel loose because the contact is now bent out of place.

Also you might have a plug that securely fits the OD but it has too large a hole in the inside so it's a poor fit. I've previously killed equipment
like that (2.5mm plug on a 2.1mm socket -> poor contact -> voltage drop -> switching converter has to pull more current to keep up -> fried something).

I think a series of drill bits to measure the ID is a good plan, then maybe there's some way to measure the OD while getting 'acceptable' tension on the spring?

Theo

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

On 6/16/2025 2:03 PM, Theo wrote:

Are there any other *mechanical fitting* issues that I may have
overlooked (obviously, there are electrical issues)?

The trouble with 'just try it' is that the 'trial' sockets can wear over

Yes, but any "test" that looks for mechanical fit suffers from that
same problem. What you really want is a way to measure without
introducing any other physical object.

Female plugs are relatively easy to sort out -- dial caliper for
the OD and a small selection of drill bits to VISIBLY probe the ID.

But, this only works for two-conductor plugs.

time. eg if you insist on putting a 6mm OD plug into a 5.5mm OD socket,
it might go but bend the spring contact. Eventually the 5.5mm OD plugs will feel loose because the contact is now bent out of place.

Also you might have a plug that securely fits the OD but it has too large a hole in the inside so it's a poor fit. I've previously killed equipment
like that (2.5mm plug on a 2.1mm socket -> poor contact -> voltage drop -> switching converter has to pull more current to keep up -> fried something).

Exactly. A fair bit of tension in the (receptacle) spring that secures the
OD of the plug can lead you to thinking it's a good fit -- because it is
next to impossible to move the plug purely laterally under that sort of
tension to see if there is a half millimeter of "play".

I think a series of drill bits to measure the ID is a good plan, then maybe there's some way to measure the OD while getting 'acceptable' tension on the spring?

Had manufacturers not wasted so much "label space" on a verbose
"- ---(O--- +" style polarity indicator, they could have included
a single character "code letter" to indicate the dimensions of the
mating plug.

But, manufacturers tend to be ignorant of the needs of their
customers -- too much "bother" to sort out.

[Notice the number of products that don't indicate a manufacturer,
model number, etc.? "We take great pride in our products -- NOT!"]

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

On 6/16/2025 2:57 PM, John R Walliker wrote:

It should be possible to make an adapter using the chip from a
cannibalised Dell PSU.  I intend to try this.

A number of years ago, while working for a company that repaired
laptops, I built a jig using a 190W Dell power adapter, and a switch to
select which ID chip to connect to the third pin. So we could test the
ability of the laptops to ID specific adapters. The one-wire protocol
is not difficult and I considered using a microcontroller to spoof the
various messages, but we had lots of adapters with bad cables so it was
easier to rob them for the part.

I did build a gizmo that would read the ID, so we could test adapters
before shipping them back to the customer.

--
I'm part of the vast libertarian conspiracy to take over the world and
leave everyone alone.

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)