The chilling news came just days before U.S. Robotics shipped its x2 modems: the FCC won't let modems transfer data at a rate faster than 53 kbps. The legal snafu has to do with a long-standing FCC regulation known as Part 68, which was never intended to affect modems. The problem is that if you send too much power through the phone line, your conversation can get loud enough to creep into neighboring lines. This is called crosstalk, and Part 68 was meant to prevent it. But to reach 56 kbps, the new modems must send more power down the line.
I've seen bad caps in a power supply raise the negative or positive DC rail to 60-ish volts above ground (basically 1/2 of the 120V AC input). If the parallel port was not properly grounded to the chassis, it would float at 60V above ground, but have very little current due to the high source impedance of the cap. A cheap voltmeter with 1000 ohms/volt with a FS reading of 100V would result in a current of 1 mA flowing, which (if the source impedance were 100,000 ohms) would make the reading on the meter half the actual open circuit value.
I had a high-end video card with a cable TV input do this - the shield of the cable input F connector (without anything connected to it) would float at 30-60V.
Many older 'DC' train systems were half- or full-wave rectified AC, so the peak voltage is much higher than the RMS value.
As for the parallel port vs case, I've found that the leakage voltage as read by a voltmeter reads very low - very low current leakage sources are loaded down by the meter.
Another data point - I've worked on telephone circuits 'barehand' without shocks, and that's 48VDC. If the phone rings, THAT HURTS - it's about 90V @ 20Hz.
Not unless you're somehow abnormally conductive. 12V DC is undetectable in normal circumstances. Standards vary, but the low voltage limit for dry locations is usually between 48 and 60V DC.
Do you have 9V batteries? Put a fingertip across one - nothing. Hook the + of one into the - of another. Touch the two remaining terminals with fingers on the same hand. Nothing.
Your tongue, however, is extremely good at detecting current flow. A 9V battery on the tip of the tongue is not comfortable.
'Internetworking' predated Ethernet by a long shot. One could argue that the UUCP network was the progenitor to or perhaps the first incarnation of the Internet - it had file transfers, email, usenet news, and was a loosely-managed, cooperative network of systems across companies, universities, and government. It was mostly modem-based; those with dedicated leased lines were the envy of all.
It was store-and-forward, explicitly routed, and relied on config files like this. Contained within this example is my UUCP node definition from 22 years ago. I'm not tellin' which one.
So get a bigger one. I have a Synology 1010+ for home use and love it. I have all my VMs on it connected to VMWare as an iSCSI disk. It works flawlessly, and having the two GB Ethernet ports bonded makes transfers pretty fast. If you outgrow it, you can add a 5 bay expansion chassis and keep growing.
The UI is good, and they have lots of packages you can install to do other 'server-like' things.
Ever tried to start a lead-acid vehicle in -50C weather? Yeah, that's what a block heater is for.
You're correct that the ampacity of lead-acid batteries drops as the temperature drops, but the other big item in the equation is (or was) the viscosity of the oil in the engine block. With modern 5W20 oils, this is less of a problem than in the straight 30W days. Note that a block heater heats the block, not necessarily the battery - otherwise it'd be called a battery heater.
That would involve "Actual Police Work (tm)". Can't have that. Why didn't the police fingerprint the stuff that I know the intruder touched when I had a break-in some years ago? Too much trouble.
1000 times this. They succeeded in getting a vaccine for a NON-COMMUNICABLE disease mandatory for girls in Texas (since partially reversed), but are still trying to get it to be mandatory for boys, too.
Instead of using glue that's difficult to remove, why not use the same stuff that's used in those 3M Command removable wall hangers? When you need to separate the components, just give the little strip a tug and the glue pops right out!
There are better ways to accomplish what you want - you can switch quickly between dedicated receive antennas to obtain samples across all those bands effectively* simultaneously. Frequency agile receivers do that all the time.
*We're talking discrete sampling here, so as long as you can switch antennas (PIN diodes) as fast or faster than the (possibly under-) sample rate and the settling time of the receiver when the frequency is changed, the receiver will have no idea there's more than 1 antenna. As the English say, "Bob's your uncle!"
Please. Our high for today is forecast to be 103 F / 39.4 C with high humidity. Lately (here in Richmond VA) our LOWS have been higher than the highs in Portland, OR where my brother lives. He loves rubbing that in. At least I don't have moss growing on me.
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Not if you include obesity.
56k modems in the US are/were limited by FCC regs to about 53k.
From this url:
The chilling news came just days before U.S. Robotics shipped its x2 modems: the FCC won't let modems transfer data at a rate faster than 53 kbps. The legal snafu has to do with a long-standing FCC regulation known as Part 68, which was never intended to affect modems. The problem is that if you send too much power through the phone line, your conversation can get loud enough to creep into neighboring lines. This is called crosstalk, and Part 68 was meant to prevent it. But to reach 56 kbps, the new modems must send more power down the line.
Read up on the ideal gas law. Remember, Piv equals nert.
Coal: Mine, crush, burn.
You left out a step: Coal: Mine, crush, burn, dispose in atmosphere
Speaking of pancakes, wouldn't those be the CREPES OF WRATH?
I've seen bad caps in a power supply raise the negative or positive DC rail to 60-ish volts above ground (basically 1/2 of the 120V AC input). If the parallel port was not properly grounded to the chassis, it would float at 60V above ground, but have very little current due to the high source impedance of the cap. A cheap voltmeter with 1000 ohms/volt with a FS reading of 100V would result in a current of 1 mA flowing, which (if the source impedance were 100,000 ohms) would make the reading on the meter half the actual open circuit value.
I had a high-end video card with a cable TV input do this - the shield of the cable input F connector (without anything connected to it) would float at 30-60V.
I would've gone with Hava Nagila.
Many older 'DC' train systems were half- or full-wave rectified AC, so the peak voltage is much higher than the RMS value.
As for the parallel port vs case, I've found that the leakage voltage as read by a voltmeter reads very low - very low current leakage sources are loaded down by the meter.
This article is interesting.
Another data point - I've worked on telephone circuits 'barehand' without shocks, and that's 48VDC. If the phone rings, THAT HURTS - it's about 90V @ 20Hz.
Not unless you're somehow abnormally conductive. 12V DC is undetectable in normal circumstances. Standards vary, but the low voltage limit for dry locations is usually between 48 and 60V DC.
Do you have 9V batteries? Put a fingertip across one - nothing. Hook the + of one into the - of another. Touch the two remaining terminals with fingers on the same hand. Nothing.
Your tongue, however, is extremely good at detecting current flow. A 9V battery on the tip of the tongue is not comfortable.
'Internetworking' predated Ethernet by a long shot. One could argue that the UUCP network was the progenitor to or perhaps the first incarnation of the Internet - it had file transfers, email, usenet news, and was a loosely-managed, cooperative network of systems across companies, universities, and government. It was mostly modem-based; those with dedicated leased lines were the envy of all.
It was store-and-forward, explicitly routed, and relied on config files like this. Contained within this example is my UUCP node definition from 22 years ago. I'm not tellin' which one.
Speaking of ethernet, anyone else remember thick ethernet cable and vampire taps?
So get a bigger one. I have a Synology 1010+ for home use and love it. I have all my VMs on it connected to VMWare as an iSCSI disk. It works flawlessly, and having the two GB Ethernet ports bonded makes transfers pretty fast. If you outgrow it, you can add a 5 bay expansion chassis and keep growing.
The UI is good, and they have lots of packages you can install to do other 'server-like' things.
And Barry Bonds, and James Bonds, ...
Ever tried to start a lead-acid vehicle in -50C weather? Yeah, that's what a block heater is for.
You're correct that the ampacity of lead-acid batteries drops as the temperature drops, but the other big item in the equation is (or was) the viscosity of the oil in the engine block. With modern 5W20 oils, this is less of a problem than in the straight 30W days. Note that a block heater heats the block, not necessarily the battery - otherwise it'd be called a battery heater.
Editor-at-Large
Editor? Certainly not. Large? Most probably.
That would involve "Actual Police Work (tm)". Can't have that. Why didn't the police fingerprint the stuff that I know the intruder touched when I had a break-in some years ago? Too much trouble.
1000 times this. They succeeded in getting a vaccine for a NON-COMMUNICABLE disease mandatory for girls in Texas (since partially reversed), but are still trying to get it to be mandatory for boys, too.
There are rumblings of money changing hands in California over the passage of the so-called "Gardasil Bill".
Even the Wall Street Journal says mandatory Gardasil injections are a bad idea.
Really low-mass spacecraft launches are more expensive per kilogram; that's just the way it works.
Not if you're AMSAT - we often get low mass launches for free* as space-rated ballast.
(*Free to launch, but not free to certify space-worthy).
... we still don't understand a single symbol of Linear A ...
Linear Algebra was hard for me, too.
... very clearly ordered mankind in the Genesis to multiply and populate all the lands.
We've done that. He didn't say "multiply and over-populate all the lands". Can we please put the "contraception is evil" one to rest?
Instead of using glue that's difficult to remove, why not use the same stuff that's used in those 3M Command removable wall hangers? When you need to separate the components, just give the little strip a tug and the glue pops right out!
There are better ways to accomplish what you want - you can switch quickly between dedicated receive antennas to obtain samples across all those bands effectively* simultaneously. Frequency agile receivers do that all the time.
*We're talking discrete sampling here, so as long as you can switch antennas (PIN diodes) as fast or faster than the (possibly under-) sample rate and the settling time of the receiver when the frequency is changed, the receiver will have no idea there's more than 1 antenna. As the English say, "Bob's your uncle!"
Not true. All direct conversion and superheterodyne receivers contain circuitry that oscillates at the receiver's IF frequency. A very small amount of that RF leaks out and can be detected from nearby. Radar detector-detectors use this technique.
The story goes that the TV van in England uses IF detection to find TVs that are not licensed, but much doubt has been cast on this story.
The only open question is about the frequency.
You must be talking to Kenneth.
Please. Our high for today is forecast to be 103 F / 39.4 C with high humidity. Lately (here in Richmond VA) our LOWS have been higher than the highs in Portland, OR where my brother lives. He loves rubbing that in. At least I don't have moss growing on me.
"It's there to explain why some particles have rest masses...the Higgs mechanism is there to explain the rest."
I see what you did there - punny!