OT: just a suggestion

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On Sat, 26 Dec 2015 20:00:29 -0500, Joseph Gwinn
I don't know what you did but you made your post unquotable, so I won't.
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On Dec 26, 2015, krw wrote

That’s odd. There are some gremlins in the middle of my reply. I’ll repost, with the center deleted.
Joe Gwinn
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On Dec 26, 2015, krw wrote

Here is the missing bottom of my reply:

All these modems take an incoming bit stream and convert it to a series of line symbols on the wire (or fiber or radio wave). These line symbols are designed to be easy to tell apart, even after having been distorted and corrupted a bit on the line, so the receiving modem can tell with very high reliability which line symbol was sent, thus recovering the original bit stream.
Because only a known set of line symbols are sent, and nothing in between, the receiver can assume that the intended line symbol is that one that is closest to one of these known line symbols.
Design of such symbol sets is a career, and there is a large literature, but a good place to start is any college textbook on data communications.
Joe Gwinn
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On Sun, 27 Dec 2015 11:05:07 -0500, Joseph Gwinn

The V.90/92 modems used phase shift key, detecting a phase shift in an analog carrier. Only offering a 0 or a 1 whether the carrier is phase shifted or not. DSL is also PSK.
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other is analog.
Analog signals are signals af varying frequency and intensity. You can get a good signal, a weak signal, or a bad signal
Digital signals are a pulse train of ones and zeroes. There is error checking built in - and you either get a signal or you don't. No such thing as "fringe reception" If you get the sinal the digital to analog converters decipher the code, and/or codecs in firmware decode the signal to audio and video signals,
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On Sat, 26 Dec 2015 22:52:47 -0500, snipped-for-privacy@snyder.on.ca wrote:

OK, I'm all for tautologies as arguments. ;-)

IOW, DSL, ADTV, Satellite TV, Cell phones, and just about everything else that's considered "digital". You will get errors, retries, data drop, freezes, and all that jazz before it drops the connection completely.

OK, so the question remains, is v.90 digital or analog?
Your "distinction" isn't, either.
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krw wrote:

sequence of 0's and 1's, then even if it is transmitted in an analog fashion, then it's *digital*. E.g. Computer files are digital. A paper tape is digital. While, not an expert about them, I would say that a cassette recording is not digital.
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On 12/26/2015 10:56 PM, Bill wrote:

Well what about cassette tape backups of data on a hard drive?
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Leon wrote:

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LOL. :-)
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Not really... Except we didn't have hard drives in those days. If we had diskette drives we were doing good. (Everyone seemed to have the 1541 if they had a Commodore 64, though.)
I've always wondered if we'd be successful playing an old computer's cassette "recording" over the phone line to another computer that was listening for it. Basically, convert the cassette ports in to a modem. I know it's an extremely convoluted and pathetic way to do it, but sometimes that's reason enough to do it!
Puckdropper
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Make it to fit, don't make it fit.

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Puckdropper says...

Probably not. A cassette has a good bit more bandwidth than a phone line. But sounds like a fun thing to try.
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On Sun, 27 Dec 2015 10:48:13 -0500, "J. Clarke"

communication without error correction is virtually useless - and the best results were well jnder 99%. (If I remember correctly we achieved better than 80% -)so we went to "plan b" with the Telex tape duplicator and "sneakernet" to distribute the programs.
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On 12/27/2015 8:52 AM, Puckdropper wrote:

a thermal heat print terminal/computer terminal. With a keyboard and a dual cassette deck on top I would communicate with our inventory control service provider, Reynolds and Reynolds. I would run a routine from that terminal to generate a stock order, get the results, and record them on a cassette, they looked like the common cassette. From there I flipped a series of toggle switches and typed in a phone number to GMPD's computer and their computer communicated with my terminal and read the cassette. The response of their computer was sent back and recorded on the other cassette on my terminal. And finally my terminal read the cassette and answer from GMPD and printed the results on that terminals thermal heat print paper.

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wrote:

recieve the data - which implemented error checking and correction.
A lot of those early modems used "accoustic couplers" - you placed the handset of the phone onto the coupler and it "talked" to the phone to transmit the modulated signals. I think that worked all the way up to about 200 baud. - mabee 300. That was about the limit for data transmission on the audio tape too.
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Even then I thought the R&R service was archaic. A few years later we switched to ADP and it was like we switched to the current century. Then we built a new facility and had ADP in house. I loved that system.

had to temporarily use the handset coupler, the regular modem had not yet arrived. IIRC one or the other accomplished 300.
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was something like 80 baud? Mabee it was 110 - it was an old Ti, I think. Went to a wired 300 very quickly.
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On Sun, 27 Dec 2015 14:52:45 +0000, Puckdropper wrote:

I started playing with microcomputers with 2 8" floppies - then 5.25" - then 3.5". Each time either the capacity or the speed went down. I knew they couldn't last :-).
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On Sun, 27 Dec 2015 19:21:18 +0000 (UTC), Larry Blanchard

used were somethink like 80kb Shugart hard sectored, then 360kb soft sectored, then up to DSDD 1.2mb. The 3.5" disks started at 280 (which never went anywhere) then 360 single sided, 720 double sided, and 1.44mb DSDD (or HD).
Then came the Flopticals, LS120 and LS240 3.5 disks with 21, 120, and 240MB capacity.and a few other nonstandard (Proprietary) systems that were ineffective to varying degrees.
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snipped-for-privacy@snyder.on.ca says...

Flopticals were nice at the time. I still have a final-generation floptical USB drive that gets used occasionally when someone needes to read a 3-1/2 inch diskette. One neat trick was that with the right driver they could get something like 16 meg on a standard diskette.
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