Question on AC grounding - found an old device that has me confused

[stj]

Re: Question on AC grounding - found an old device that has me confused

i know exactly how it worked, i had sourcecode.
the card contains a microcontroller and the contacts are a serial port,

the pc just simulates the microcontroller.

the way it works is the decoder tells the card the channel ID, and a cypher key that is encrypted.
the card then checks the channel ID against a table of what you subscribed to, and if the ID is in the table it decrypts the key and returns it to the box to decode the stream.

where we are now, is the latest boxes run Linux with the card emu onboard and can get the key data over the net in realtime.
https://github.com/gfto/oscam

[dmill89]

Re: Question on AC grounding - found an old device that has me confused

Seriously, how old of a building would you have to be in to not have a ground in your AC outlet? I'm thinking pre-1950's?

More like pre-1970s, grounding started to appear in the 1960s but didn't become universal in the US until the early 1970s.

Grounding of receptacles first appeared in the 1962 NEC (National Electric Code), but not all states/jurisdictions adopt the code updates at the same time so there can often be a decade or more from the time something new appears in the code until every state/county/city actually implements the updates (for example today some States are still on the 2008 revision of the NEC). https://na.bhs1.com/state-by-state-g...-nec-adoption/


Of course it is also common for people to (illegally) swap out 2 prong outlets with 3 prong ones without actually adding grounding (there is a legal way to do this with a GFCI and stickers indicating "no equipment ground" but many don't to this).

[EasyGoing1]

Re: Question on AC grounding - found an old device that has me confused

the tv card hack was very well known in europe,
it was dos software called "voyager"
it linked over a com port and a level shifter.

I'm wondering now if maybe that setup read the satellite signal from the back of the PCI card - might have even been an ISA card (like with its own LNB connection), then it would just configure the credit card key in the sat receiver with whatever it needed to know to decode the signal.

Do you recall how that setup worked? His was the only one that I had any knowledge of ... though I'm sure they were advertised heavily in the hobbyist electronics periodicals. My brother used to subscribe to one of those magazines, though I can't remember for the life of me what it was called. It was very popular though ... maybe even called Popular Electronics? Or ... something like that...

[stj]

Re: Question on AC grounding - found an old device that has me confused

the tv card hack was very well known in europe,
it was dos software called "voyager"
it linked over a com port and a level shifter.

[EasyGoing1]

Re: Question on AC grounding - found an old device that has me confused

we hacked the jerrold's too - a pic chip fitted to enable all channels and throwing the return "modem" in the trash.
not on the supplied box obviously - on a second (or 3rd or fourth! ) picked up used.

in the mid-2000's I was working for the local city as their network admin, and this new guy that we hired as a tech had just graduated with a bachelor degree in programming - though degree to get as it requires calculus and engineering physics ... so this guy was your a-typical propeller head ...

He took an original Pentium based clone PCs because it cost him nothing and in one of the drive slots where you would normally mount a CD / DVD drive, he had this custom made socket that attached to a PCI card via a ribbon cable on the motherboard and in that slot was a card -about the size of a PCM/CIA card and on the front of it was another ribbon cable attached to a credit card the was exactly the size of the thin plastic key cards that you insert into a satellite receiver to activate your satellite subscription.

Running on the PC was a custom operating system that somehow read signals from the card in the sat receiver and ran algorithms that could hack the signal and program the receiver to decode it.

Free satellite TV ... until they completely re-worked those scrambling signals making that pirate method null and void ... I don't remember if he ever took it to the next level or if it was even possible to descramble after the networks upgrade but it was quite an interesting project and certainly a hell of lot more complicated than 20 years prior when we just gutted a box and ran coax through it..

[stj]

Re: Question on AC grounding - found an old device that has me confused

we hacked the jerrold's too - a pic chip fitted to enable all channels and throwing the return "modem" in the trash.
not on the supplied box obviously - on a second (or 3rd or fourth! ) picked up used.

[EasyGoing1]

Re: Question on AC grounding - found an old device that has me confused

exactly, they said "Jerrold" on the front and had a 2 digit display and a keypad ontop.
(and spied on your viewing using a return channel!)

YUP! I remember!

Before they had any kind of digital decoders, they use to put these filters out on the telephone pole where the cable came into the property that would actively filter out HBO if you didn't pay for it.

Well, my brother - being the resourceful guy that he was ... got a ladder to get himself to the first pegs on the pole, then he went up the pole and remove the filter - he had to cut a section out of a socket because they had the nuts inside a sleeve around the coax making it impossible to loosen it without the "special tool" so he just sliced off part of a socket and that did the trick.

When he got it off the pole, he opened it up and gutted it and connected both sides with straight coax and then put it back on the pole, that way if they ever came by to inspect, it would look as if the filter was still on.

He was maybe 13 years old when he did that.

We got free HBO for a long time on that little venture.. lol

[stj]

Re: Question on AC grounding - found an old device that has me confused

exactly, they said "Jerrold" on the front and had a 2 digit display and a keypad ontop.
(and spied on your viewing using a return channel!)

[EasyGoing1]

Re: Question on AC grounding - found an old device that has me confused

the construction reminds me of old General Instrument (GI) cable boxes.

I remember them ... didn't they make the first cable tv decoder boxes for pay channels?

[televizora]

Re: Question on AC grounding - found an old device that has me confused

They still make 2-prong extension cords and three conductor cords are less physically flexible and heavier than two conductor cords.

These are only excuses. The weight matters only in USA. For example, our outlets and extension cords are exclusively Shucko /Well, sometimes Europlug can be seen for smaller devices/. Nobody will connect the chassis to mains and use one pin of the Europlug as ground, hoping that he will not electrocute somebody. It is a well known fact that US outlets and plugs are notoriously unsafe, excuse me, but this is the truth. Not only this, but the socket itself does not provide any support for the plug and the plug can just pop out of the wall. With guiding notches and recesses many other types of plugs and sockets eliminated this flaw. I have to say that the stupidity, seen on the pictures in the first post combined with not so well designed sockets and plugs represent shock hazard. I fail to understand how this box passed any certification at all. If it was me to certify it, I would just throw it out of the window.
I also have to underline that if you used your plugs and sockets with 230V, there would be dead people, for sure. Some of us even have 380V in our homes, for larger kitchen appliances or instant water heaters.
Boxes and other stuff should be Class II appliances - double insulated. Otherwise adequate grounding means MUST be provided.
There should be no way for mains to be able to get onto the chassis.

[stj]

Re: Question on AC grounding - found an old device that has me confused

if it isnt branded, radio shack didnt sell it.
maybe it came from a cable company or with some security camera stuff
it's too solidly build to be from a computer/games company.

the construction reminds me of old General Instrument (GI) cable boxes.

[EasyGoing1]

Re: Question on AC grounding - found an old device that has me confused

I didn't think RatShak was so bad to sell (under their name) things that could kill people

To be fair, I did not see a Radio Shack brand on this device nor the other brand that they manufactured and sold under ... was it Realistic? I know Tandy was their computer line ... I can't remember ... but there was no branding on this thing at all, it just LOOKED like a device that Radio Shack would make and sell back in the day.

[EasyGoing1]

Re: Question on AC grounding - found an old device that has me confused

-But ohh, what if the customer don't have a grounded outlet?
Well that's his fucking problem then, isn't it?

Seriously, how old of a building would you have to be in to not have a ground in your AC outlet? I'm thinking pre-1950's?

[eccerr0r]

Re: Question on AC grounding - found an old device that has me confused

They still make 2-prong extension cords and three conductor cords are less physically flexible and heavier than two conductor cords.

The device also marks UL - so it theoretically is UL listed and thus tested for electrocution hazards. I didn't think RatShak was so bad to sell (under their name) things that could kill people, so I would have suspected the resistor or capacitor. As a device that actually creates radio frequencies they had to make it so that it doesn't generate too much RF, and the hope that the FCC symbol printed indicates it also passed part 15 rules...

[stj]

Re: Question on AC grounding - found an old device that has me confused

you will be dead if you touch the chassis.

unlikely in a country that doesnt have *real* mans voltage.
(yes, i spelt "mains" wrong! )

[Per Hansson]

Re: Question on AC grounding - found an old device that has me confused

Yep, the high value resistor (see posts #8 and on) makes it "sorta ok" in the old days.
It is still retarded though: because if there is a failure in the 20 cent Chinesium transformer that puts the primary across on the secondary and it finds a way over to the ground:
Well then there is no low impedance return path to the breaker, so the fuse wont trip, and you will be dead if you touch the chassis.
There can be other failures too that cause this, like a wire coming loose from that 0.01 cent crimp connector for example.

All this stupid shit is to reduce interference in sensitive equipment that require a ground to work properly to begin with.
Well here is an idea: use a fucking cord with aground then you numbwit manufacturers!
-But ohh, what if the customer don't have a grounded outlet?
Well that's his fucking problem then, isn't it?

[EasyGoing1]

Re: Question on AC grounding - found an old device that has me confused

Only the ground terminal of an outlet can be connected to the chassis of a device, if it is not ClassII - Double insulated. This is wrong. Perhaps it relies on a plug with a 3rd dummy pin, so you cant reverse the plug. But it's still wrong. Replacing the plug or improperly wired outlet could lead to you being electrocuted. If these were our unpolarized sockets, there would be dead people.

I think it's been determined that the inline 1.5 MΩ resistor would be sufficient at keeping people from dropping dead... if I had not ripped the thing completely apart, I might have run some tests on it... but under the assumption that it was just a straight connection, I wanted nothing to do with it ... other than harvest the cord for a different device and the transformer for an unknown future project.

[EasyGoing1]

Re: Question on AC grounding - found an old device that has me confused

I bet there is a resistor (1~5meg?) in that heat shrink between ground and the line neutral wire, and it is NOT directly connected. There is usually a capacitor (0.01µf) across the resistor as well but not always.

No cap, but yes, there was a 1.5 Megaohm resistor in there.

[R_J]

Re: Question on AC grounding - found an old device that has me confused

I bet there is a resistor (1~5meg?) in that heat shrink between ground and the line neutral wire, and it is NOT directly connected. There is usually a capacitor (0.01µf) across the resistor as well but not always.

[stj]

Re: Question on AC grounding - found an old device that has me confused

polarised - sort-of