What is the bandwidth of your snax? How fast is your internet in bananas?
It is a common way to measure and MEME almost anything with a banana scale. There is now a banana scale for Internet speed: bananas transmit at about 53mbps on vdsl btw. VDSL over Banana is real – the tester got 53680/12658 kbps connection speed on a short run from in-house exchange/DSLAM, through banana, to a VDSL2 modem.
Here is a tweet from https://twitter.com/lauriewired/status/1735348312684020069 (also tweted at https://twitter.com/Evil_Mog/status/1709671970957386230)

It’s official, ADSL works over wet string Engineers at a small British internet service provider have successfully made a broadband connection work over 2m (6ft 7in) of wet string. The connection reached speeds of 3.5 Mbps (megabits per second). ADSL itself is something of an ingenious hack, carrying data over decades-old telephone wires designed only for voice. Some employees of Andrews & Arnold (a UK network provider) applied this mentality towards connecting their ADSL test equipment to some unlikely materials. The verdict of experiment: yes, ADSL works over wet string.

Here is picture of the experiment from https://www.revk.uk/2017/12/its-official-adsl-works-over-wet-string.html article.

According to those experiments it seems that you can use anything that is electrically conductive to transmit data signals in a way or another. In other news, materials that conduct electricity can be used to transmit signal. Marvelous finding lads!

Could you do that even without strings attached?
Can You Send The Internet Through Water Instead of Cables? The Literal Web Streaming Experiment!
https://www.youtube.com/watch?v=nEg9R7kcrIo

A lot of data goes through water, but using fiber optic cables instead of using the water itself as medium. There is a lot of data going under the sea. What’s more, 98% of the world’s internet cables are located undersea. This includes around 400 underwater cables around the world.

How The Internet Travels Under Sea
https://www.youtube.com/watch?v=LEM_I3HbIU8

How about telecommunications or fast data over barbed wire? Yes this has been done also.

Barbed wire fences were an early DIY telephone network. In some early years of telecommunication, even over 100 years ago, fences became phones: The unexpected use of barbed wire. A party line (multiparty line, shared service line, party wire) is a local loop telephone circuit that is shared by multiple telephone service subscribers. Party line systems were widely used to provide telephone service, starting with the first commercial switchboards in 1878. Barbed wire telephone lines were local networks created in rural America around the turn of the 20th century. In some isolated farming communities, it was not cost-effective for corporations to invest in the telephone infrastructure. Instead, the existing extent of barbed wire fences could be used to transmit electric signals and connect telephones in neighboring farms. Nowadays VDSL can be done over a farm fence if you want internet access or a security camera somewhere inconvenient.

But can you run Ethernet over barbed wire? In 1995 Broadcom showed it’s implementation of a subset of Fast Ethernet called 100BASE-T4 (different from the 100BASE-TX version that ultimately prevailed in the market). The value of the Broadcom T4 design was its ability to work at high speeds on horrible cables, so Broadcom wanted to demonstrate its operation using the world’s worst cable.

At Interop that year, Broadcom set up a 2×4-ft glass case containing eight parallel strands of barbed wire configured as four differential pairs, each running straight from side to side, suspended in air. The wires were ugly and rusty and had nasty little barbs all over them. A transmitter and a reel of Category 3 data cabling were on one side of the case. The data cabling led to the glass case where it coupled onto the four barbed-wire pairs. The other side of the case coupled through more Category 3 cabling to a receiver. They showed that 100 Mbit/s Ethernet can run over this kind of poor looking wiring sing their technology. During the show, lo and behold, Broadcom’s demonstration flawlessly conveyed 100 Mbps of data through the barbed wire. “Buy our parts” was the message the Broadcom marketing folks wanted to impress on their audience. There was also a display of this in action at COMDEX in Vegas (2000).

In year 2002 WideBand Gigabit Ethernet Over Barbed Wire was on display. WideBand Corporation has been showing its Gigabit Ethernet Without Rewiring by using barbed wire to make the point at trade shows from coast to coast this spring. WideBand has used its barbed wire demo as a way to underscore the robust transmission capability of its Ethernet products.

So how is it possible to use this kind of poor looking wiring for high speed data?
Only four properties really affect the performance of most digital transmission structures. The “big four” transmission-line properties are impedance, delay, high-frequency loss, and crosstalk. Crosstalk in a barbed-wire configuration is controlled by enforcing a large spacing between the pairs. The T4 system divides its data among the four pairs, so that each pair operates at only 25 Mbps. At that low frequency the skin-effect resistance of 4 ft of barbed wire is insignificant, and the overall high-frequency loss in the glass case at 25 Mbps was practically nil. The signal delay is less on barbed wire than on an equivalent length of PVC-insulated Category 3 wiring, due to the use of an air dielectric between the barbed strands. You can intentionally set the spacing to create almost any impedance you want. Inside the glass case, the spacing between barbed strands was set to create an impedance of 100 Ω.

In summary, the barbed wire had zero impact on signal quality. The signals went through perfectly undistorted. The only thing the barbed wire did was impress the heck out of Broadcom’s customers.

Besides Ethernet running over many barbed wires, the are also demos that run high speed data over one pair of barbed wires. Westermo has demonstrated Ethernet extension based on SHDSL technology running over a pair of barbed wire. The wire pair doesn’t have to be barbed wire, but it does look rather cool for this demo. If you need to run data over barbed wire over some real distance, this might be the practical way to do it. SHDSL technology allows running quite high data speeds over quite long distance old wiring.
Westermo Ethernet extender demo over barbed wire!
https://www.youtube.com/watch?v=LP3amXkjvPg

Links to more information on ADSL over wet strings:

https://www.revk.uk/2017/12/its-official-adsl-works-over-wet-string.html
https://hackaday.com/2017/12/14/adsl-robustness-verified-by-running-over-wet-string/
https://www.zdnet.com/article/fact-broadband-really-does-work-over-a-piece-of-wet-string
https://www.techpowerup.com/forums/threads/dsl-broadband-over-wet-string.239701/

Barbed wire Ethernet links:
https://www.sigcon.com/Pubs/edn/SoGoodBarbedWire.htm
https://www.wband.com/2002/05/wideband-gigabit-ethernet-over-barbed-wire-catches-fancy-of-national-magazine/
https://www.reddit.com/r/networking/comments/17g0b4/ethernet_over_barbed_wire/
https://www.quora.com/Is-it-true-that-someone-ran-Ethernet-over-barbed-wire-and-if-so-WHY
https://news.ycombinator.com/item?id=15910263
https://forums.tomshardware.com/threads/gigabit-over-barbed-wire.958476/

Barbed wire telephone links:

Phones, modems and barbed wire!
https://www.wanderingaustralia.com.au/the-phones-are-driving-me-mad/

Barbed Wire Telephone Lines Brought Isolated Homesteaders Together
And then let them snoop on each other
https://www.atlasobscura.com/articles/barbed-wire-telephone-lines-homesteaders-prairie-america-history

When fences became phones: The unexpected use of barbed wire
https://www.kttn.com/when-fences-became-phones-the-unexpected-use-of-barbed-wire/

Atrocious but efficient: How ranchers used barbed wire to make phone calls
A barbed wire telephone call didn’t sound great but could quickly warn others about something such as a wildfire.

https://www.texasstandard.org/stories/atrocious-but-efficient-how-ranchers-used-barbed-wire-to-make-phone-calls/

https://en.wikipedia.org/wiki/Barbed_wire_telephone_lines

https://www.agriculture.com/podcast/successful-farming-podcast/barbed-wire-telephones-connected-the-old-frontier

Barbed Wire Fences Were An Early DIY Telephone Network
https://gizmodo.com/barbed-wire-fences-were-an-early-diy-telephone-network-1493157700

The Daily Herald
Delphos, OH, United States, Thursday, April 19, 1900
vol. 6, no. 266, p. 3, col. 5-6
BARB-WIRE TELEPHONE LINE.
Three Towns in Indiana Connected by Using Ordinary Fence Wires.
https://reference.insulators.info/publications/view/?id=5740

TEXAS HISTORY
Wired for Sound
Between you, me and the fence post, barbed-wire telephone systems kept rural folks hanging on every word
https://texascooppower.com/wired-for-sound/

Video
BARBED WIRE TELEPHONE LINE
https://www.youtube.com/watch?v=koEkQ3EqyNk

The use of public telephones was common at the time and phone cards were seen as the cutting edge of development. Those were first launched on a large scale in 1986 in Germany by Deutsche Bundespost after three years of testing, and in France by France Télécom. Many other countries followed suit, including Ireland in 1990 and the UK circa 1994–1995. Tele (nowadays known with name Sonera) was the first to use phone card machines in Finland. Tele and several local telephone companies switched coin-operated telephones in telephone booths to card-operated telephone models in the early 1990s.

The cards had a certain amount of balance loaded at the time of purchase using chip technology. The first phase technology was technically quite simple and not very secure. But by the mid-to-late 1990s, highly secure technology aided the spread of chip phonecards worldwide.

The whole phone card technology was somewhat short-lived (especially in Finland) because in the late in the 1990′s they became unnecessary as cell phones became more common (thank’s to Nokia), which led to situation that the the previously common telephone booths disappeared from the street scene. Here are pictures of one 30 years old not so smart telephone booth calling cards used in Finland.

This type of telephone cards are the simplest type of “smart card”. The cards had a certain amount of balance loaded at the time of purchase, and this amount was stored to the card. Those telephone cards (as used in Finland and France) were technically simple memory card with smart card connector. This kind of memory cards only have some amount of memory inside the card and this memory can be normally read and written. There is normally nothing really intelligent inside those cards. There is a memory chip that has a small amount of card information it followed by memory are that contains the information of balance in the card.

A stored-value phone card stores the available balance in digital memory physically embedded in the card. This balance can be read by a public payphone when the card is inserted into the card reader. The stored-value system used in Finland write data to an embedded chip to reflect the new balance after a call. Used primarily for payphones, stored-value systems avoid the time lag and expense of communication with a central database, which would have been technically complex before the 1990s. In Finland the card had a memory area, where there was one memory bit for each token (30 mk card had 30 tokens) value in card. The tokens could be freely read, and one by one written to “used” state after use (but could not be turned back to not used state).

The technology worked, but it was not the most secure as a href=”https://en.wikipedia.org/wiki/Telephone_card”>the initial microchips were easy to hack. Some users found out that some cards could be hacked by scratching off the programming-voltage contact on the card, which rendered the phone unable to reduce the card’s value after a call. Also some people have built their own cards that looked like phone card to the phone, but they did not decrease the stored amount during use or were automatically reset back to card balance full state when removed from card. This kind of hack cards could be built at the time using a small thin circuit board and a small micro-controller soldered to it running a small program that emulates phone card operation.

I was interested in how those cards worked in the early 1990′s. I looked the technical information related to them and built my own hardware+software that allowed my PC to communicate with them.

Hacker magazine PHRACK issue 48 (September 1, 1996) published a two part article on electronic telephone cards technology. That article also mentions some of my work on the field (I improved some of the card communications software published in the article). The software enables you to dumb the memory of electronics phonecards to see the information in them. The software also allowed to write to cards (write out some bits to lower the balance).

You can find the article parts here:
Electronic Telephone Cards: How to make your own! (part 1)
Electronic Telephone Cards: How to make your own! (part 2)

Here are some picks from those articles:

{*****************************************************************************}
{ T E L E C A R D . PAS }
{*****************************************************************************}
{ This program enable you to dumb the memory of electronics phonecards }
{ from all over the world, so that you will be able to see which country }
{ the card is from how many units are left and so on …. }
{*****************************************************************************}
{ }
{ Written by Stephane BAUSSON (1993) }
{ }
{ Email: sbausson@ensem.u-nancy.fr }
{ }
{ Snail Mail Address: 4, Rue de Grand }
{ F-88630 CHERMISEY }
{ France }
{ }
{*****************************************************************************}
{* Thanks to: Tomi Engdahl (Tomi.Engdahl@hut.fi) *}
{*****************************************************************************}

After the information was more widely on-line, more and more people figured out how to hack those phone card to get free calls. People hacked those card and sold fake cards in Finland to the point that phone companies had to start to try to catch the users of fake phone cards and magazines started to write about the problem.

Here is one article from 1996 on the phone card hacking problems in Finland:
Puhelinkorttien jäljitelmillä huijattu ilmaisia puheluita Tele joutui korjaamaan tuhansien yleisöpuhelimien suojausta
” Poliisi tutkii Suomessa ensi kertaa paljastuneita puhelinhuijauksia, joissa on puhelinkorttien jäljitelmien avulla huijattu ilmaista soittoaikaa. Simulaatiokorteiksi kutsuttujen jäljitelmien avulla huijari on voinut soittaa ilmaiseksi kuinka kauan tahansa.”

Just few years later the system started to shut down because in addition to free calls problems the increasing owning of of mobile phones started to make phone booths not as profitable anymore as it once was.

Sources:
https://en.wikipedia.org/wiki/Telephone_card
https://www.epanorama.net/links/smartcards.html#memorycard
https://www.turku.fi/blogit/kukkuu-kokoelmista/kokoelmanosto-kuvat-kortilla-yleisopuhelimien-lahihistoriaa
Electronic Telephone Cards: How to make your own! (part 1)
Electronic Telephone Cards: How to make your own! (part 2)
https://groups.google.com/g/sfnet.harrastus.elektroniikka/c/k2yqfJVb_aA/m/fqmm4nNa4MwJ
https://www.hs.fi/kotimaa/art-2000003536142.html
https://www.antikvariaatti.net/kerailyesineet/puhelinkortit

Almost clever!
You can actually plug in US charger to speakon connector and have it to make contact with two “pins” (1- and 2-).
You can power a 110V mains device with the output of a powerful audio amplifier that outputs high amplitude 50 or 60 Hz (or something close enough for device to accept it, many small chargers can accept quite wide frequency range). Dave Rat has video where he powers one PA amplifier from the speaker output of another one.
This can be made to work if you want to put effort to it, but generally does not work well.

Video: Wall Voltage From and Audio Amp & Does Hot AC give more Watts? (Public)

The presented ideas are not directly adaptable to faster twisted pair wiring Ethernet standards (1G, 10G etc.) because they use all the four wire pairs for communicating at both directions.

First start with the standards.

IEEE 802.3i standard (1990) defines 10BASE-T 10 Mb/s twisted pair Ethernet communications.
A 10BASE-T transmitter sends two differential voltages, +2.5 V or −2.5 V. Typically 10BaseT transmitters built so that they inject current to line and receivers sense received voltage. The signal bandwidth is 10 MHz.

IEEE 802.3u standard (1995) defines 100BASE-T Fast Ethernet that works on 100 Mb/s speed. A 100BASE-TX transmitter sends three differential voltages, +1 V, 0 V, or −1 V. The signal has most energy at bandwidth of 31.25 MHz, but there are some signal components that the signal occupies a very broad frequency range up to over 100 MHz.

100BASE-TX and 1000BASE-T were both designed to require a minimum of category 5 cable and also specify a maximum cable length of 100 metres (330 ft). Category 5 cable has since been deprecated and new installations use Category 5e or 6. 10BASE-T and 100BASE-TX require only two pairs (pins 1–2, 3–6) to operate. The cable is specified to have differential impedance from 85 to 115 ohms. The cable is designed to have low cross-talk by twisting the pairs to cancel interference. 100BASE-TX follows the same wiring patterns as 10BASE-T, but is more sensitive to wire quality and length, due to the higher bit rates.

Twisted pair to 75 ohm coax with video baluns

Twisted pair Ethernet is designed for 85 to 115 ohms impedance twisted pair. Having a cable that is nicely balanced and has a tight twist rate helps in overall performance of the cable. What I am aiming to do it transfer the signal over 75 ohms coaxial cable (unbalancaed media). RG59 with both solid center conductor (RG59B/U) and stranded center conductor (RG59A/U) as well as RG6 are 75 ohm coaxial cables often found in video applications and installed to building.

To get the Ethernet signal from twisted pair to coax and back would need to adapt both impedance and balanced/unbalanced nature of signal). Fortunately there are widely available cheap tools designed for this: Traditionally analogue video transmission is done using 75 ohm coaxial cables. Those video signals are not directly compatible with nowadays more widely used twisted pair wiring (CAT5, CAT6 etc..), which means you just can’t wire the signals directly form video output to a twisted pair wire and get good results. Video signal can be adapted to UTP wiring using a video balun between BNC video connector and the twisted pair wiring.

To do the do balanced-unbalanced conversion with impedance is to put some suitable balun transformer between Ethernet card and coax cable. Many passive Video baluns originally designed to interface 75 ohms coax video signal to 100 ohms UTP cable on the “wrong way”.

It depends on the video balun construction how well they work with Ethernet signals. with 10M Ethernet it is expected that quite many video baluns would work as the frequency range used fits quite close to typical video signal range (up to 6-10 MHz).

With 100M there is higher frequencies up to around 30 MHz, so baluns that are limited to 10 MHz or lower might not work acceptably, but baluns that advertise HD resolutions support work with higher bandwidth signals can work up to 30 Mhz to almost 100 MHz depending on balun design and construction quality.

Here is my experiment with two cheap “no name Chinese” video baluns connected to around 16 meters of 75 ohms antenna coaxial cable. For my testing I connected two baluns to the ends of coaxial cables and RJ-45 connector one wire pair carrying the signal (pins 1 and 2) and let the other pair (pins 3 and 6) go straight through normally.

Because this was just for test purposes, I did the adaptation for only one data direction of Ethernet connection. The Ethernet connection seems to work well without problems. For a real-life applications, I would need to have another coaxial cable and two baluns for that to let all the signals to go through coaxial cable. This proof of concept worked at this cable length at 10 and 100 megabits per seconds speeds without noticeable issues.

To carry the signals you would need two 75 ohms coax cables (one for RX and other for TX) and four baluns. In 100 Mbit ethernet over cat5 cable, there actually is a dedicated
transmit and receive. So you can’t easily replace both with a single piece of coax.

G.703/G.704 impedance matching baluns do not work for Ethernet

Several manufacturers make promising looking baluns 75 120 ohm are used for G.703/G.704 impedance matching purposes. They have two coaxial connectors and one RJ-45

This type of connectors are designed for international WAN environments. Specifically created for the ITU-T/CCITT G.703 TELECOM applications, the balun provides conversion between 75 Ohm and 120 Ohm G. 703 interfaces. Typically this type of adapters support data rate up to 2.048 Mbps (E1) and some promise also support for 8 Mbps. For those of you who may not be familiar with G. 703, it is similar to T1 or DDS standards in the USA. This interface standard is used throughout the world to specify the physical and electrical characteristics which enable the interconnection of digital network components. For example G703 is the connection standard for E1 services in Europe. This balun simply converts 75 Ohm G. 703 transmit signals to 120 Ohm signals for transmission over network, or reception by a CPE. Many adapters list that the twisted pair side can be 120 ohms or 100 ohms impedance.

This type of adapters come depending on manufacturers and models with two different pin-outs on RJ-45 side: (1,2,4,5) or (5,4,6,3). Neither of those pin-outs match the pins used by 10/100M Ethernet (1,2,3,6). Other issue is that the bandwidth of many of products is advertised to be 2.048 Mbit/s, so most probably they might not perform well at 10 MHz (for 10 Mbit/Us Ethernet) or at 32 MHz (100 Mbit/s Ethernet). I have not tested, but I think that the adapters that are designed to support also 8 Mbit/s data speed, could work somehow at 10 Mbit/s speed if you build a custom RJ-45 cable that adapts the Ethernet pinout to data pin pinpout used by the balun.

Information sources:
https://www.ad-net.com.tw/all-about-impedance-converters/
https://www.alibaba.com/product-detail/G703-Balun-75-Ohm-to-120_60301276025.html
https://www.temple-star.com/ITU_T_CCITT_G703_Telecom_Balun.htm
https://www.alibaba.com/product-detail/16-Channels-75-Ohm-BNC-To_60386281089.html
https://cables24.com/en/coaxial/balun/balun-module/1241-balun-75-120-ohmrj-45-female-dual-bnc-female-g-703-e1-e3
http://www.e1-converter.com/G703_Balun/75_ohm_to_120_ohm_Coax_to_RJ45_Balun_Panel.html

Experimenting with 75 ohms cable without baluns

The next question for experimenting was could this work even without baluns? I have earlier tested that Ethernet can run somewhat outside that 85-115 ohms impedance in many cases OK. I tested Ethernet to work in the range 75-80 ohms on my earlier tests. So the 75 ohms coax impedance could be “close enough” as such. So it might work if you are lucky at 75 ohms impedance many coax cables have close enough impedance for 10/100 M Ethernet. To carry the signals you would need two 75 ohms coax cables (one for RX and other for TX).

Connecting the signal to coax cable has it’s challenges, because Ethernet cards are designed to drive balanced wire pairs, while coaxial cable is unbalanced. To do this adaptation correctly, a balun should be used.

But on some cases could could live without balun. Ethernet interfaces use transformer isolation for transmitted and received signals, and in most cases the line side coils are “floating”. In such case a direct connection to unbalanced coaxial cable could work (but it is not guaranteed to work always, because there are cards where the line side coils have center taps that can be connected to termination resistors and/or power-over-ethernet electronics). Those with Ethernet transformer line side coil grounded in some way (typical especially in PoE systems), trying to drive coaxial cable is expected pretty much fail without balun.

On my tests the devices I used had Ethernet transformer output coils completely floating, and worked OK when connected to coaxial cable. Here is picture of my experimenting with the same 16 meter coaxial cable where I directly connected the Ethernet card to coaxial cable directly in the same way where I earlier used video baluns.

The Ethernet signal seemed still work OK on short test.

Commercial converters for one 75 ohm coax

There are also commercially made Ethernet to 75 ohm coax cable converters designed for video surveillance applications. Video surveillance systems have traditionally used 75 ohms coaxial cable to carry analogue (and later in some cases digital) video signal from camera to surveillance center. When IP based digital cameras have become popular, there has been interest to run Ethernet signal over single 75 ohm coaxial cable from surveillance center to the IP camera.

It is not physically impossible to send data over a single cable in both directions at the same time. There are many communications systems that do that (PSTN, gigabit 1000BASE-T, etc.). The challenge is that you need to somehow subtract the local TX contribution to get the RX part. And you have to make sure the TX contribution doesn’t get fouled up by the RX contribution. The problem is that this all has to work with, in the case of 100BaseT, pretty fast rise times. And you need to maintain 75-Ohm termination at both ends.

Usually this is done nowadays using active electronics, but some companies have succeeded to design a multiplexter that does 10base-tx or 100baseT to coax conversion system with passive components only.

There are several different products marketed for this, some are active devices and some are completely passive devices. For passively adapting 10/100M Ethernet to single 75 ohm coaxial cable, there are product like Monoline Coax Balun – Male BNC to RJ45 jack 10BaseT – 75 Ohm – Each and IP Passive Extender Ethernet Over Coax 1-CH, IP Network to Coaxial Transmitter IP Network Converter Fit CCTV Camera UTP RG59/ RJ45 4-Wired 1236 Cable No. BNC Video Balun Only Fit POE Camera System.

Direct connection to many 50 ohms coax cables

What if we want to connect twisted pair Ethernet to 50 ohms coaxial cable (old Ethernet coax or 50 ohm RF antenna cable)? There are several experimental ways that allows 50 ohms coax to be used on some cases.

You can use two 50 ohm single ended coaxial cables for single 100 ohm differential signal, unless there is something special that prevents it. I have seen many applications where micro-coax is used for differential signals. For example display panels with LVDS or eDP, and a I-PEX VS type connector.

The impedance is depending on the ratio of capacitance and inductance between the two conductors. Two 50 Ω coax to ground in “series” will result in 100 Ω differential impedance (“throug” the ground). The right 100 ohms differential impedance is what Ethernet wants. Both pieces of coax need to be of equal length for this to work. Cat 5 cable is 100 ohms differential, which is exactly what you want. This coaxial solution uses two 50-ohm cables for the two arms of a differential signal, giving 100 ohms differential.

Here are some notes on the impedance from Maxim application note:
As shown in Figure 4, coupled cables (STP, UTP, twinax) derive their differential characteristic impedance both from coupling between the (+) and (-) lines of a pair (Z1), and coupling of each side to ground (Z2, Z3). Any imbalance in a differential pair, such as asymmetry of length, or twist, or dielectric environment (in which Z2 ≠ Z3), causes a differential-to-common-mode conversion with measurable symptoms, such as intrapair skew.

There are some differences on properties. The single-ended impedance seen by Ethernet card is somewhat different with two coax cables approach, but that is not significant issue and devices can live with it. The single-ended properties of each transmission line in a twisted pair are terrible. This is not very controlled impedance. The single-ended impedance of the cable varies down its length, depending on the position of the local conductors. The typical common impedance of an unshielded twisted pair will vary from around 100 Ω to 200 Ω. As long as there are no common signals on the twisted pair, you don’t need to care about the common impedance. The challenge is preventing common signals from getting on the twisted pair.

For more information on impedance matching between coax and twisted pair, check out following links:
https://electronics.stackexchange.com/questions/391254/non-coaxial-50-ohm-cable-for-lvds
https://www.eeweb.com/interfacing-lvds-to-pecl-lvpecl-cml-rs-422-and-single-ended-devices/
https://www.pulseresearchlab.com/pages/necl-pecl-faqs
https://ez.analog.com/clock_and_timing/f/q-a/20074/ad9517-lvpecl-output-interface-to-a-fanout-buffer

If you had four 50 ohms coaxial cables of same length, you could use then to carry one 10/100m Ethernet connection just by wiring the signal carrying pins to the center pins of coaxial cables and connecting the shield of coaxial cables carrying signal together on both ends. In real life applications using four coaxial cables is not usually practical.

50 ohms coax with baluns

The same balun trick that I used with 75 ohm coax can be used with 50 ohms cable. Ideally you should use 50 ohms to 100 ohms baluns, but because they are rarely needed they are usually hard to get and expensive.

For a shortcut test I tried to use 100 ohms to 75 ohms baluns with 50 ohms cable. I found out that 100 ohm to 75 ohm video baluns can also work with 50 ohms cable. I tested with video balun and around 10 meters of RG-58 cable. It worked.

With those 75-100 ohm video baluns when cable is 50 ohms, expect to to get around 75 ohms impedance on twisted pair cable instead of correct 100 ohms. It was not entirely correct, but was still close enough that it seemed to work. For 10M or 100M two 50 coax cables are needed, one for TX and other for RX. I have not tested how long cable this “hack” can support.

Old coaxial Ethernet

Experimental Ethernet started in 1972 as 2,94 Mb/s network over 50 ohm coaxial cable. 10BASE5 (also known as thick Ethernet or thicknet) was the first commercially available variant of Ethernet. The technology was standardized in 1982 as IEEE 802.3. 10BASE5 uses a thick and stiff coaxial cable up to 500 meters (1,600 ft) in length.

10BASE2 (also known as cheapernet, thin Ethernet, thinnet, and thinwire) is a variant of Ethernet that uses thin coaxial cable terminated with BNC connectors to build a local area network. In 1985 10BASE2 10 Mb/s “thinnet” was released, it used 50 ohm RG-8-like coaxial cable. 10BASE2 uses RG-58A/U cable or similar for a maximum segment length of 185 m.

During the mid to late 1980s 10BASe2 was the dominant 10 Mbit/s Ethernet standard. 10BASE2 coax cables have a maximum length of 185 metres (607 ft). The maximum practical number of nodes that can be connected to a 10BASE2 segment is limited to 30. Ethernet segments have to be terminated with a 50 ohm resistor at each end of the cable.

Due to the immense demand for high speed networking, the low cost of Category 5 cable, and the popularity of 802.11 wireless networks, both 10BASE2 and 10BASE5 have become increasingly obsolete, though devices still exist in some locations. As of 2011, IEEE 802.3 has deprecated 10BASE2 standard for new installations

Using other coaxial cable types with 10BASE2

If you have some 50 ohms coaxial cable (does not need to be exactly like RG-8 or RG-58) you want to use for Ethernet, 10 megabits is enough and you have suitable old Ethernet hardware around, then you can try to run Ethernet over it.

Coaxial cables also come in various impedances — typically 50, 75 and 93 ohm. 50 ohm coaxial is used typically for radio transmitters and for Ethernet. 75 ohm cable does a better job of maintaining signal strength and is primarily used for connecting any type of receiving device such as CATV receivers, high-definition TVs and digital recorders. Originally used in mainframe IBM networks in the 1970s and early 1980s, 93 ohm coax is rare and expensive special cable.

ANSI/TIA-568-4.D specifies requirements for 75 ohm broadband coaxial cabling, cords and connecting hardware to support CATV, satellite television and other broadband applications. For the Cabling Subsystem 1 between the outlet and the first distribution point, the length limit is 46 meters for RG6 and 90 meters for RG11. For a Cabling Subsystem 2 between distribution points, the length limit remains at 46 meters for RG6 and increases to 100 meters for RG11. For each of these deployments, TIA-568-4.D specifies insertion loss limits over the frequency range of 5 to 1002 MHz.

What if you have 75 ohm TV antenna coax run instead? There was once an obsolete computer network standard 10BROAD36 that was designed to support 10 Mbit/s Ethernet signals over standard 75 ohm cable television (CATV) cable over a 3600-meter range. 10BROAD36 was less successful than its contemporaries because of the high equipment complexity (and cost) associated with it. It was forgotten and replaced later with cable modems.

What about using 10BASE2 hardware with 75 ohms coax? Of course, there will be an impedance mismatch between the 10base2 transceivers (50 Ohms) and the TV coax (75 Ohms). Some energy of the signal will be lost due to reflection. An impedance mismatch like that is generally a bad idea. It’s not just the energy loss, but the reflections rattling all over your circuit can lead to interference. There are many stories of 10BASE2 networks being crippled to very slow speeds when someone by accident installs a piece of 75 ohms cable to it.

Use of all 75 Ohm cable may work in some cases. It might work well or not. Here is one report from https://groups.google.com/g/alt.cable-tv/c/3se4xxQ-z48 says:
“But the 10Base-2 is based on 50ohm RG58 thin coax cable. And CATV is
supposed to be based on 75ohm RG59 thin coax cable.
Go ahead, it’s going to work quite well. I have tried it at home on my 10base2 network and it did work. My cables are all RG58 (50 ohms) and someone asked the same question as you, I was curious and I spliced in 100 feet of RG59 (with all the adapters from “f” connectors to BNC) and not a singleerror. Obviously you would not want to go 185 meters with RG59, but between two rooms or inside a house, no problems.”

Yes, RG58 can be used, and yes, you can sometimes get away with RG59. In technical point of view the problem in using 75 ohms is impedance matching issue between Ethernet designed for 50 ohms in many ways. The Ethernet terminators are (supposed to be) 50-ohms (so cards transmitting will see 25 ohms load9. When connected to the ends of 75 ohms cable, instead of terminating all the signal hitting them, they will reflect back significant part of it. If you used regular 75-ohm TV terminators on the correct termination impedance would stop the signal reflections, they would ‘increase’ the impedance of the cable seen by signal transmitter to 35-ohms. The higher than expected impedance potentially can cause issues with the collision detection of the Ethernet network, that is based on transmitters sending a known current to line and monitoring the voltage on the line (it gets higher when two stations are transmitting). When cable system is higher impedance than right one, the voltage produced by one transmitter gets closer to “collision detect” limit that it should.

Article at https://groups.google.com/g/alt.cable-tv/c/3se4xxQ-z48 says:
“The terminators, by the way, must be 50 ohms at each end regardless of the impedance of the cable. Yes, this is an impedance mismatch to the cable, but it is required by the *DC* signalling requirements of 10-Base-2. If you’re using RG59 and so you thought you’d need 75-ohm terminators, it may limp along, but collision detection will no longer be reliable and so there will be even more retries by the upper layers… If your cable runs are reasonably short, the 75 ohm cable will probably work.”

With 50% more resistance than you’re supposed to have, the receivers will see 50% more voltage than they were designed for. Since collision detection is based on seeing more voltage than a single transmitter’s current would imply, you end up with a collision whenever you try to talk.

Also said at https://groups.google.com/g/alt.cable-tv/c/3se4xxQ-z48:
“The terminators, by the way, must be 50 ohms at each end regardless of
the impedance of the cable. Yes, this is an impedance mismatch to the
cable, but it is required by the *DC* signalling requirements of
10-Base-2. If you’re using RG59 and so you thought you’d need 75-ohm
terminators, it may limp along, but collision detection will no longer
be reliable and so there will be even more retries by the upper
layers…”

When we put 50-ohm terminators on 75-ohm cables, there will be some reflections. But the *DC* signalling mechanism in 10-Base-2 requires 50-ohm terminators, i.e., a 25-ohm DC load. The reflections aren’t usually too much of a problem with short cable lengths and small numbers of taps (preferably just point-to-point connection). A lot of folks in this thread have reported getting away with using RG59. If you can connect the connections at both ends and you are sure their are no other devices connected to the cable and the devices you are connecting on each end are supposed to be connected to each other, it could work. If you have old Ethernet hardware laying around to test, then feel free to test. Well if it works, let’s leave it like that. If it does not work, maybe forget the idea. I don’t think it would be worth of trouble trying to hunt down or buy old 10BASE5 hardware for testing.

There are some impedance matching transformers, but generally 50-to-75-ohm baluns won’t work with 10Base2 because they don’t typically preserve the DC levels. Passive resistor based impedance matching circuits on the other hand cause lots of signal attenuation.

Yes, RG58 can be used, and yes, you can sometimes get away with RG59. I wouldn’t suggest
it for a business, but for home use it could work (especially with simple point-to-point links). Even if “it works” with your RG59, look at your NIC and protocol error counters. Look for collisions, bad packets received, retries, etc. You might be unpleasantly surprised. You see, it may be “working” but only because your upper level protocols are doing far more retries
than you would really like. This can hurt throughput in a big way.

This kind of LED hat is something that makes hacker mind spinning. The hat had wireless connection so, can anynone hack their “Mobile APP Bluetooth connection”? I think sending random nasty words to nearby hats could be funny if those become popular. Or sell a large number of other person’s hats as advertisement space for good money. Those were just few ideas that could be illegal to try, so best not to implement them.

Another ideas are that this is something that some hardware hackers must have made tried to make themselves. And yes they have. With Arduino and with LEDs like WS2812 this kind of ideas can be implemented quite easily. Here are some related DIY ideas for hardware hackers:

https://blog.adafruit.com/2018/06/06/gif-playing-led-hat-how-to-wearablewednesday-wearabletech-diy-arduino-tech/
https://www.instructables.com/id/Fancy-LED-Hat/
https://makezine.com/2013/09/03/the-awesome-led-hat/

https://www.bunniestudios.com/blog/?p=3554
Some SD cards contain vulnerabilities that allow arbitrary code execution — on the memory card itself. On the dark side, code execution on the memory card enables a class of MITM (man-in-the-middle) attacks, where the card seems to be behaving one way, but in fact it does something else. On the light side, it also enables the possibility for hardware enthusiasts to gain access to a very cheap and ubiquitous source of microcontrollers.

I did some fault finding and contacted IKEA. Anyways this product was supposed to have 10 years guarantee. Nothing in the manual helped to solve the issue.

When contacting IKEA I got this tip: First, try resetting to factory settings:

* Check that the pin / key is properly seated. The pin / key is located on the front panel of the table top. Unplug the power cord for at least a minute, preferably several hours, and then plug it in again
* Press and hold both adjustment buttons for at least 10 seconds to reset the base to the factory settings.
* If the stand does not work as it should, please contact our customer service.

That did not solve the issue. I tried to do this few times but nothing. I tried disconnecting and re-connecting the cables but it did not help.

I did some measurements try to find what is wrong. The table base has a mains power supply (looks quite much like laptop power supply) that is supposed to output 35V DC at few amperes to power the motors that move the table. I measured the output voltage and the transformer was putting out slightly less than 24V DC. This is not right.

After few contacting IKEA they sent me a new power supply (and also new control buttons), but it did not solve the problem. :-(  Finally IKEA swapped the motor base to a new one, and that made the table to work again.

When I had to fiddle with the board, I also looked around what information about this able is available. Here is what I found:

IKEA Bekant Table Hacking project page shows how to add memory functions and make it controllable with serial cable. The reason why this was done because the project developer thought that only simple “Up” and “Down” buttons installed by default pretty much sucks. There is IKEA Hackant Github page with more details.

Smarkant page shows how to convert your IKEA Bekant table into a smart IoT device. The ESP8266 can give us WiFi and quite some processing power to implement a REST interface to control our table remotely.

Hacking an office desk page is a project description in Finnish on controlling this desk with Arduino. This project connects Arduino to the existing control button electronics so that Arduino emulated up and down key pressing. This project uses the ultrasonic sensor to get the current height (could be read from LIN bus).

IKEA Bekant Älypöytä Arduinolla page is a project description in Finnish on controlling this desk with Arduino. This project connects Arduino to the existing control button electronics so that Arduino emulated up and down key pressing. This project page has nice picture on what is inside the slight hard to open control buttons case:

On Github there are pages: https://github.com/robin7331/IKEA-Hackant and https://github.com/trainman419/bekant and https://github.com/robertaramar/bekant

More project pages: https://www.henrirantanen.fi/2015/03/10/ikea-bekant-arduino-alypoyta/

There are also two interesting videos on this topic:

That IKEA Bekant Table Hacking page has interestgin information that Robert Nixdorf had found out that the used the LIN protocol for control buttons to communicate with the motors. Here is a nice video on hacking the LIN bus of this table:

Let’s look on that a little bit more on LIN bus:

LIN (Local Interconnect Network) is a serial network protocol designed to be used for communication between components in vehicles. The need for a cheap serial network arose as the technologies and the facilities implemented in the car grew, while the CAN bus was too expensive to implement for every component in the car. In the late 1990s, the LIN Consortium was founded by five automakers (BMW, Volkswagen Group, Audi, Volvo Cars, Mercedes-Benz).LIN is a broadcast serial network comprising typically of one master and up to 15 slaves. The master and slaves are typically microcontrollers. LIN uses single wire communications up to 19.2 kbit/s @ 40 meter bus length. It is designed for typical 12V operating voltage. It is a low-cost, single-wire network based on ISO 9141.

The trick is that this classic video game is made out of discrete components — it is 100% IC free. I like the beauty of it’s complex wiring! Look at the video of it:

There is also a nice project page at http://www.glensstuff.com/videopong/videopong.htm that describes the project, including the full interesting circuit diagram.

Atari’s original arcade Pong from 1972 was hybrid analog/digital, but made extensive use of digital IC’s (74xx, 93xx, etc.)

AKG D60S Technical Description

Frequency Range: 70 Hz to 20 kHz

Polar Pattern: Hypercardioid

Sensitivity: 2 mV/Pa (-52 dBV)

Impedance: 500 ohms

Size: 50 x 176 mm (2 x 6.9 in.)

Weight: 230 g

With technical devices that are in use, it sooner or later comes day when they get damaged. In my case the the microphone wire mesh-grill got damaged due age and dropping of microphone. The plastic construction inside the wire-mesh grill is completely broken to peaces beyond sensible repair.

Because this is microphone model was discontinued quite long time ago, it is practically impossible to get original replacement grill.

So I have to come up with some alternative. It seems that the way this grill is screwed to mic body seems to be similar to one found in Shure SM58 microphone.

Ordered generic SM58 replacement groll from China (Wish.com) and paid few three euros for it (one euro for part and two euros postage).

After two weeks waiting I finally received the package. But I was was not happy because the product was not packed well enough to withstand the heavy hit it must have too from China to here.

This seem to have damaged beyond being useful, possibly beyond repair. Got full refund when I sent those pictures to the shop. They said I can keep the damaged product and do whatever I want with it.

So having nothing to loose, I decided to try if I could make this still somehow work until I get a new replacement from somewhere.

I tried few things to change the shape, but the grill seemed to need quite a bit of force to change shape.

To have enough force, I decided to take this kind of hammer and try if it could be used to do something useful. It could either help or completely destroy what I have. I was willing to take the risk.

After some careful hitting from different directions, I got the grill to pretty nicely to the right almost round shape. I was amazed that it worked this well.

The grill even fit to the mic and I got everything working. I needed to added a small rubber-band type rubber seal on the bottom of the treads next to microphone body to make everything fit well in place (due slight incompatibility with the screw threads).

All wind shield sponge and this look like new!

This was today’s hardware hack. This was real hacking of hardware to make it work!