
Anatomy of a cheap USB-to-Ethernet adapter - dshankar
http://projectgus.com/2013/03/anatomy-of-a-cheap-usb-ethernet-adapter
======
jrockway
I appreciate the shielding Apple added, especially with two resonators in the
HF band. The shielding is, BTW, probably to prevent the device from causing
interference, not to prevent other devices from interfering with it. (It's not
a radio, after all.)

Note that if you do choose to buy the cheaper one without any shielding, it's
your responsibility (in the US) to prevent it from interfering with licensed
users of the RF spectrum. (In this case, 25m shortwave broadcasters on 12MHz
and government-run time-transfer services, like WWV and WWVH, on 25MHz.)

If your device is particularly annoying to some shortwave listener, expect to
get a letter from the FCC telling you to shut the thing off.

(I looked up a few of the letters, and I really appreciate the politeness from
the government:
[http://www.arrl.org/files/file/Part%2015%20Letters/04-06-24-...](http://www.arrl.org/files/file/Part%2015%20Letters/04-06-24-Battery%20Charger.pdf)
"There are several simple and inexpensive steps that can be taken to eliminate
interference from battery chargers, and we would be glad to send them to you
if needed.")

~~~
streetnigga
The complainant even provided the fix (Toroid cores, often seen as those lumps
on USB cables) for free, installed and everything. In response the emitting
neighbor went and...

"You apparently discarded the toroid devices, tossing them in Mr. (deleted)
yard. The devices were simple and non-intrusive, and we can envision no reason
whatsoever for you not to continue using them, other than a desire to be
uncooperative."

Dabbling in RTL-SDR for a bit quickly brought me up against the interference
monster, and since the USB sticks are typically powered by bus if no direct
power modifications are done one of those sources of interference was hooked
right into the receiver. Toroid cores either clipped on or looped were indeed
the answer for quieting the cable. This doesn't help much if the interfering
device is emitting really badly off the board itself though so manufactures
shielding their devices as a standard is rather welcome.

~~~
jrockway
A few letters in, the guy was still being a jerk about it:

[http://www.arrl.org/files/file/Part%2015%20Letters/04-09-29-...](http://www.arrl.org/files/file/Part%2015%20Letters/04-09-29-Battery%20Charger.pdf)

~~~
streetnigga
Dang jrockway, stop looking at my house so hard.

------
mdisraeli
According to Bunnie's investigation into microSD cards[1], that low serial
number probably indicates that the components were produced on a "ghost
shift", when a rogue worker comes in at night and runs the plant off the books

[1]
[http://www.bunniestudios.com/blog/?page_id=1022](http://www.bunniestudios.com/blog/?page_id=1022)

~~~
hayksaakian
Great read. thanks for the link.

------
selectodude
I'm equally impressed by the Apple adapter. They make expensive stuff, but
they legitimately don't cut corners. It's nice to see there's still one
consumer electronics company that still does that.

~~~
Vecrios
What do you mean by "[Apple] don't cut corners"? Serious question.

~~~
pndmnm
As one possible example, see Ken Shirriff's teardowns of a cheap USB power
adapter: [http://www.righto.com/2012/03/inside-cheap-phone-charger-
and...](http://www.righto.com/2012/03/inside-cheap-phone-charger-and-why-
you.html)

And an Apple adapter: [http://www.righto.com/2012/05/apple-iphone-charger-
teardown-...](http://www.righto.com/2012/05/apple-iphone-charger-teardown-
quality.html)

~~~
learc83
Most of that had nothing to do with Apple not cutting corners.

The Apple device is UL listed, so they can't cut the same corners the Chinese
manufacturer can. The same is true of any UL listed USB power adapter.

~~~
wyager
Very few UL power adapters are as good as the ones Apple makes. I ran a bunch
of my USB charger "cubes" at medium load and looked at their output on my
o-scope one time. Most of the UL listed adapters had way more noise than the
Apple one, even at just 500mA. There was one other manufacturer's charger that
was as good as the Apple charger, but I can't remember off the top of my head
who it was... I think it might have been HP or Asus or something.

------
userbinator
The lack of shielding is rarely any problem. Two oscillators is not better
than one, since PLLs can generate the required clocks (480MHz = 25 / 5 x 96,
100MHz = 25 x 4, 125MHz = 25 x 5); SMSC has some USB/Ethernet solutions that
use the same 25MHz frequency.

> The Windows drivers are the exact same digitally signed ones that Microsoft
> distributes through Windows Update

AFAIK there is a standard device class for "USB ethernet controllers", so any
chipset that conforms to it will work fine with the standard drivers.

As for the unmarked chip - many IC companies are not averse to creating custom
designs for a specific customer (and marking it however you want) if you're
willing to buy enough. I don't think it's ASIX since they don't have the
single 25MHz clock source; more willing to bet on Microchip or SMSC.

~~~
angusgr
(Blog author here)

You're spot on about the PLL stage, a few people on Reddit pointed the same
thing out when I first posted it. Makes sense, although I still think it's
interesting they added it internally to an otherwise (apparently) cloned
design.

You're also right that USB CDC does provide the option for a generic USB
Ethernet device, however this silicon is ASIX-specific (not just the USB IDs.)
ASIX's Windows drivers include their own system driver binaries, and the ASIX
Linux driver has a lot of ASIX-specific stuff in it.

I think it's kind of possible ASIX made this themselves as some kind of no-
name branded unadvertised market segmentation effort. I can't understand what
their rationale would be exactly but hardware companies do unusual things
sometimes...

~~~
userbinator
If you go only on the definition of a clone being "compatible interface", then
there are tons of other examples of that in the electronics industry - it's
more commonly known for simpler parts like voltage regulators (how many
companies make a '7805?), opamps, transistors, etc. but also occurs with more
complex ones too.

IC companies make unadvertised products all the time, for anyone who is
willing to buy enough... look at Apple's Lightning cable and TI's BQ2025, for
instance.

------
Tomdarkness
I recently purchased a Gigabit ethernet adapter for my rMBP. If you're fine
with something a bit larger and are willing to go above "dirt cheap" I'd
strongly recommend the Inateck HBU3VL3-4. It's made by a German company so I'm
not sure how available it is over in the USA.

It has an ASIX AX88179 which is a USB 3.0 to Gigabit chip and it my tests I
was easily able to get around 800-900Mbps. It also has 3x USB 3.0 ports, so
not only do you not lose your USB 3.0 port you gain 2 more. I've not
dismantled it but it feels solidly built.

Here in the UK I paid the same price as the Apple USB to Ethernet Adapter,
which is only 100BASE-T and offers no hub.

~~~
darrenkopp
Fantastic, I'm in the market for a USB gigabit ethernet adapter as the
thunderbolt one from Apple (and all other thunderbolt adapters it would seem)
disable the sleep on windows. I found this on Amazon in the US under the brand
"Unitek."

[http://www.amazon.com/gp/product/B00EHDNAOE/ref=as_li_ss_tl?...](http://www.amazon.com/gp/product/B00EHDNAOE/ref=as_li_ss_tl?ie=UTF8&camp=1789&creative=390957&creativeASIN=B00EHDNAOE&linkCode=as2&tag=diaryofamadma-20)

------
gresrun
We have used a similar dongle at our company for a 2nd ethernet adapter on our
Foxconn-built boxes and found out that they usually don't have unique MAC
addresses. This made our lives very difficult because Cobranet audio network
uses level-2 addressing. We eventually found a supplier with real MAC
addresses.

~~~
userbinator
You know it is usually pretty trivial to assign whatever MAC you want to them.

(I have an unbranded Android phone that assigns a _random_ MAC address every
time I turn WiFi on/off. Apparently this happens since they didn't bother to
initialise the EEPROM and just left it at all zeroes. But this means being
harder to track, so I consider it more a feature than a bug...)

~~~
rahimnathwani
Does it have a legit IMEI? I've read about phones with IMEI set to all zeroes
and/or configurable in a secret menu. What model is the phone?

~~~
rahimnathwani
To clarify, my interest in whether the IMEI is zeroed and/or programmable is
about how the various mobile networks use IMEI, particularly: - China Unicom
uses them to detect continued use of subsidized handsets on their network (and
will send the customer a text if they're not using it (eg if they've sold
their subsidized phone) - I believe T-mobile USA use IMEI to limit access to
their 'free data for life' promotion to specific tablet models - Several UK
mobile networks have different data tariffs for phones vs. tablets vs. dongles
vs. mi-fi devices I'm wondering whether there is any/widespread use of these
android devices to bypass restrictions and, eg use a cheaper tablet data plan
on a mobile phone with tethering to multiple devices.

------
analog31
An old analog hacker rule of thumb is that if your product is going to emit
RF, you'll find spurious RF on input and output terminals (including ground
terminals), which you can check with a scope. Such a pre-test is cheaper than
getting a field test done and failing.

The scope test might be do-able on a comparison basis between the two designs.
It's possible that Apple over-engineered their shielding.

It's not necessarily a cloned design. The cheap part may simply implement
standard protocols, and use the name of the Apple part to ensure driver
compatibility without too much testing. Still, that seems rather under-handed
if it's what it seems.

------
catch23
Good article. It reminds me of the stories Wozniak would tell about his chip
reduction techniques back when microchips were really expensive.

------
Eduardo3rd
OP isn't alone - I find these parts dissections fascinating as well. Posts
like these show you how and why hardware is becoming a comodity. It's going to
be a very interesting century.

------
aroch
>I’d love to learn more about these secretive industries and the engineers who
work in them.

Isn't it pretty well known that 1) they aren't secretive and 2) they don't
actually design their own hardware. They start off by producing the legitimate
item, in the factory that's contracted by the company who designed the
product. If the product is successful or easily fits in their existing
knockoff fabs, they plans are basically copied over

~~~
gbog
They aren't secretive, but they are hungry, and they are foolish.

I'd venture the shanzhai chinese geeks fiddling relentlessly with hardware in
Guangzhou are much closer to Steve Jobs' ideal than the average Apple Store
clients.

On one side you have rich kids who can afford a $30 dongle, knowing perfectly
(after reading this article) that they are giving away $25 to a marketing
department and that they are bowing to their own voodooish cargo cult. These
guys are simply afraid of the remote possibility of having to spend 5 mn of
their precious time checking a connection, and maybe too, something really
catastrophic! lose ONE of their 10.000 instagram pizza photos because of a
subpar component in their setup.

On the other side you have these ugly hackers who are photocopying hardware
components for 1 year old companies named
Yunxingdianziguangzhoujituanyouxiangongsi, and their logo is ugly, and these
guys are Chinese! I know them: they are hungry, not only hungry for money, but
also hungry for knowledge, recognition, they are curious about the world,
about the future, and they have no fear for bad taste: a pink iPhone clone
with teddy bear shape? check!

~~~
WoodenChair
It's a poor analogy for many reasons, not the least of which is to SJ: \-
Taste mattered a great deal - he definitely did have a "fear for bad taste" \-
Things being perfect and working perfectly out of the box without "5 mn of
their precious time checking a connection" mattered a great deal \- User
experience mattered more than price \- SJ wasn't interested in commodities

Also I don't know why you would refer to the guys as "ugly" and why you
exclaim that "and these guys are Chinese!" There's something subtly racial
about your view in the whole post. Would it be any less of an exclamation if
they were Peruvian?

~~~
gbog
Wow, you got it wrong: it must be my mistake, I was a bit too assuming on the
context.

\- For me being "foolish", in the mouth of Steve Jobs, means not caring at all
about what other people will say or think. I see a link with the peculiar "bad
taste" of shanzhai: they do not care what "good taste" people think of pink
Teddy bear shaped phones.

\- I am living in China since 10 years, my wife is Chinese, my kids are half-
Chinese, all my colleagues and many of my friends are Chinese. My comment was
not "subtly racial", it was (trying to be) ironically emphasising the fact
that in some people's disdain of shanzhai cheap gadgets, there is also the
fact that those who build them are Chinese.

Just like 30 years ago saying a car was Japanese meant something cheap,
copied, second-grade, right now the same applies to Chinese manufacturing.

And, in fact, often justifiably so! There are three kind of products quality
made in China:

1) The very cheap that is sold in developping countries (have you ever seen
those electric plugs with a single hair of copper inside for conductivity?
cost nothing, burns after 10mn use).

2) The high quality sold to developed countries with Western brands. E.g. the
Apple usb dongle in question here.

3) The medium quality sold internally and in developed countries as cheap
alternatives to 2) above.

By the way, this 3) class is the most interesting because as the Chinese
middle class raise its income level, it will have to become better and better,
until a Chinese brand will do better than what is imitated currently (just as
Japan did with cars, hifi, etc.).

I hear often that Chinese people cannot produce quality because of some of
their "cultural atavism", and I think this is very wrong. In the past, they
were manufacturing the best of breed in many domains, and in all their region
of influence having "北京" (Beijing) stamped on goods was enough to triple its
price.

------
naner
We use a ton of USB adapters where I work and are using them all day long with
several different systems. A few months ago we got a batch of cheap adapters
and one noticeable difference was the cheap ones get really hot compared to
the more expensive name brand adapters. Appear to work OK, though.

------
chenster
Very interesting study. Somehow in the back of my head, it still whispers "You
get what you paid for".

~~~
kalleboo
It's just a shame that it looks like your options are paying $3 for a part
that cost $2 to make, or $30 for a part that cost $6 to make

~~~
chenster
If so, why don't they make an exact clone of the Apple one at $6 cost and sell
it at $15, or even $10? The identical thing but at much better price. Win-win.

~~~
giovannibajo1
Because nobody will buy them because there is no way you can convey the fact
that being an exact clone gives more "quality" than being a cheap knockoff.
It's already a hard sell a $300 android phone from a $100 android phone,
though you would say there is infinitely more differences between the two,
compared to two usb-ethernet adapters.

Some people will buy Apple just because it's Apple and they want "original"
stuff; others will buy Apple because they read these articles and know that
the parts are high quality; others will buy the cheapest one they can find
among amazon, ebay, monoprice and korean websites (probably laughing at those
who buy Apple parts).

I don't think there's an easy market for "non-Apple and midprice".

~~~
chockablock
Oh there's a market. E.g.: Plugable USB2-10/100 adapaters use genuine ASIX
chips, have OSX drivers, and sell for $15.

(They also sell a USB3-gigE adpater for $25)

------
rahimnathwani
The taobao link in the original post leads to a listing which does not specify
the chipset or support for Mac. This suggests it's a cheaper chipset. The 4-5
best-selling cheap USB-to-Ethernet adapters on taobao use the RD9700 chipset,
and can be had for 22RMB including shipping.

The cheapest Asix 88772-based one I can find from a reliable seller is 25RMB
including shipping.

It seems like there is another 50 cents that can be cut from the design,
although the RD9700 may not have an OSX driver:
[http://forums.macrumors.com/showthread.php?t=1450026](http://forums.macrumors.com/showthread.php?t=1450026)

~~~
userbinator
The RD9700 is "USB 2.0" and what they don't tell you is that it's actallly
"USB 2.0 (FS)", i.e. the 12Mbps full speed mode.

It also comes in a 32-pin package, and comes from a shady-looking company
([http://www.corechip-sz.com/](http://www.corechip-sz.com/) ) that has parts
numbered 6872 and 6873, so the "RD6877" on the PCB of OP's clone suggests it
might be a RD6877.

~~~
rahimnathwani
Wow, good spot!

Does that mean the RD9700 devices on taobao (22RMB) are likely to work on OSX
without additional drivers, as they pretend to be an Asix chipset?

The speeds OP got are higher than 12Mbps, so I guess it's not an RD9700 in
disguise.

Just guessing. I'm about to order the 25RMB asix-type one.

~~~
rahimnathwani
For reference this is the one I'm going to order: USB网线转换器笔记本网卡以太网转网线
windows全通用型MAC免驱 [http://tb.cn/nmLpZey](http://tb.cn/nmLpZey)

~~~
rahimnathwani
I received my adapter. The windows driver (automatically downloaded from
Microsoft) reports that it's not a genuine Asix chip. The message is the same
as described in this document:
[http://www.asix.com.tw/FrootAttach/userguide/How_to_identify...](http://www.asix.com.tw/FrootAttach/userguide/How_to_identify_Authentic_ASIX_USB-
to-LAN_Products_v100.pdf)

It seems to work fine on a Mac, though.

------
14113
This is interesting - and more importantly, is there any part of the ethernet
standard they don't support? I only ask, as at my university there were a
number of networks that students simply couldn't connect to if they used _any_
ethernet adaptors. Oddly enough, thunderbolt adaptors, and ethernet on the
motherboard worked fine, just USB adaptors didn't work.

~~~
nknighthb
There have been times in the past when I've found almost every USB ethernet
adapter available on the market to be of a single chipset. If one very common
chip at that time had a poor interaction with your school's switches, boom.

Most of the time, the cheap no-name electronics I've encountered have been
pretty feature-complete, or even feature-laden, and any bugs were usually
minor annoyances rather than fatal flaws.

But the quality control is a crapshoot, so a good chunk of them tend to be
DOA. Of the ones that work fine at the start, many will fail in the following
weeks, months, and years at much higher rates than you'd expect.

------
bane
Great writeup.

So I guess the question is, is the one with the fruit on it worth $25 more? It
seems like the cheap one is more "Wozniak" in approach.

~~~
EpicEng
The problems I have run into with the cheap versions of hardware like this is
that they tend to fall apart. For example, my last mini-DVI to HDMI adapter
performed just fine... until the glue holding the female end in broke loose. I
glued it back, and then the plastic started to crack.

The guts of it (the electrical bits) looked fine, worked properly, etc. It was
the mechanical design that gave me problems. Replaced it with a (ridiculously
expensive at $29.99) higher end version and that has lasted me quite some
time.

------
noonespecial
The cheap one: looks like we're running without containment, just not enough
to cook us.

------
chrislaco
Anyone done a writeup like this, but for mdp -> dvi adapters... Apple vs
Monoprice, etc?

~~~
chockablock
Mini DisplayPort -> single-link DVI-D is just a passive cable adapter, so a
lot harder to screw up.

(And even less reason for it to cost $29, but that seems to be Apple's default
minimum price for an accessory.)

------
mariuolo
Love that blog, thanks for pointing me at it.

