My opinion is that in those cases the data itself may be binary but the transmission is not unless the delays are fixed as the delays in between bits in a digital transmition or between fixed width frames. Otherwise they carry information and are part of the transmission code so it's not binary.
First Digital Phone Call
- Thread starter djsfantasi
- Start date
My opinion.
It is on / off. That is binary. Anything else is just protocols.
Working for Collins Radio I was seeing late model (at the time) analog telephone gear in the mid 80's. I know VOIP existed around then, and we had plenty of digital gear that probably carried phone channels, but technology is like culture, sometimes it takes a while for changes to occur.
It is on / off. That is binary. Anything else is just protocols.
Working for Collins Radio I was seeing late model (at the time) analog telephone gear in the mid 80's. I know VOIP existed around then, and we had plenty of digital gear that probably carried phone channels, but technology is like culture, sometimes it takes a while for changes to occur.
Of course it is acceptable for us to have different viewpoints. And that's the most reasonable thing you have said so far, because previously you insisted that I was wrong. That is not "viewpoints" that is a hardball attitude that you were right and I was wrong.
As for WHY I continued the discussion, it is because if morse is to be classified as > base2 then it has far reaching repercussions. Many modern binary comms standards have matching characteristics to morse, so from your viewpoint they must also be > base2.
So either modern binary comms are NOT binary (because they have binary data and framing elements increase the base), or morse IS binary (because it has binary data and framing elements do not increase the base).
Those are the two "viewpoints" refined down to simplicity.
Now that looks like a backpedal to me. You are now saying morse is binary if it is represented by symbols, but it is not binary if it is sent with timed keying?NSAspook said:
So all other modern binary comms that are sent using timed periods to differentiate between the binary 0 and 1 data, and periods for framing, they are no longer binary comms?
Morse has 36 possible binary data blocks (A-Z and 0-9) which are transmitted in any way we like, with zero or more framing elements to separate data blocks.
ASCII has 128 possible binary data blocks which are transmitted in any way we like, with zero or more framing elements to separate data blocks.
Coding methods;NSAspook said:
Morse is ENCODED by substitution, using 36 binary data blocks to represent the 36 characters. It's encoding is definitely binary.
Keying methods;
Morse has been sent with different periods. It has been sent using a high tone for a 1 bit, and a low tone for a 0 bit, with the same bit period. And pauses between. It was still morse. Did that different way of keying morse change the base?
It has been sent with only 1 period length between data blocks. Only three elements; 2 data bits and framing period. Also represented in text, using 3 characters; ("-",".",framing). Did that change the base to base 3 because they only used 3 symbols? Was it still morse?
Morse is this;
Like ASCII and other binary data standards it uses only two binary symbols to represent all transmitted characters. Framing can be added to a binary comms as needed or desired. It's external to the data and external to the encoding. It is framing or formatting. It does not change the data base!
How is that encoding in the diagram above different from ASCII binary? About the only significant difference is that morse uses variable length of the data blocks. Ascii is always 7 binary bits, morse is 1 to 6 binary bits (to speed transmission).
If you think having variable data block length stops it being binary I can find some example of modern binary comms that also use variable data block length to speed transmission.
I'm not sure why people think morse has different rules than every other binary comms type. I think it's probably some hangover from analysing morse in the old days before binary comms was so widespread in so many forms and we had better defined rules.
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Your example illustrates 41 "DATA BLOCKS".
None of this is germane to the OPs question about the first digital telephone call.
We could have started with smoke signals, worked our way through radio-telegraphy, and all the secure phone schemes out there.
Was it the first "digital phone" call or the first "digital" phone call? I lost track in these five pages.
I'd go with whoever designed the rotary phone as the first "digital" phone call.
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I had the misfortune to rebuild one of the old rotary military phone exchanges with the Strowger step by step relays for rotary phones. The mechanical logic was pretty impressive as was the amount of oil and special tools needed to keep them running at full speed.
https://www.youtube.com/watch?v=xZePwin92cI
My understanding of AnalogKid's question was the first "digital phone" call. I.e., transmission of voice digitally. But you are right; the question is vague on that point and since it was identified as a trivia question, makes me wonder.
Around 1970, I visited briefly one central here in Buenos Aires that still used the pulse system. What impressed me the most was the noise (a big central with many subscribers).
Heard that tehnicians used to carry nail files to clean contacts. It seemed a little bit crude way to me.
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I doubt that, a nail file would ruin a wiping contact with the first use. we used a contact burnishing tool.
http://www.pkneuses.com/www.pkneuses.com/cont.htm
We had to test our rebuilt exchange with number pulse test inputs on all lines to verify the calling matrix. What a racket that made! Using digital for switching and encoding calls was a no brainer.
Holy Self-Clocked, Binary-Level, Pulse-Width Modulated, Return-Zero Data Stream, Batman!
The thing with Morse Code is that there is a temporal component to the data stream, basically a 3-state PWM, and it requires a phase-locked detector. The PLL that locks on to and extracts the clock and tracks the temporal component is the wetware listening to the radio. Think about designing and testing an analog PLL circuit that has a 10:1 or 15:1 capture range. Ouch.
And it wasn't a trick question. I meant a phone call as in what a phone call was decades ago: pick up the handset, signal an operator, get a connection over a wire pair, talk; and digital as in a numeric quantization of a continuous function. You know...digital.
In the 90's (1990's to be clear in this thread), Analog Devices started working analog function history into their seminars and app notes. From this we know that an analog multiplexer for telephony was patented in the late 1800's. They figured out that it had to switch faster than voice freqs or the audio went to crap, but it was decades later that Claude did the math.
What started all of this was stuff I picked up from one of the Analog Devices blurbs, that PCM was patented in the 20's, and the first digital phone call was between Roosevelt and Churchill, and it was some form of PCM.
ak
The thing with Morse Code is that there is a temporal component to the data stream, basically a 3-state PWM, and it requires a phase-locked detector. The PLL that locks on to and extracts the clock and tracks the temporal component is the wetware listening to the radio. Think about designing and testing an analog PLL circuit that has a 10:1 or 15:1 capture range. Ouch.
And it wasn't a trick question. I meant a phone call as in what a phone call was decades ago: pick up the handset, signal an operator, get a connection over a wire pair, talk; and digital as in a numeric quantization of a continuous function. You know...digital.
In the 90's (1990's to be clear in this thread), Analog Devices started working analog function history into their seminars and app notes. From this we know that an analog multiplexer for telephony was patented in the late 1800's. They figured out that it had to switch faster than voice freqs or the audio went to crap, but it was decades later that Claude did the math.
What started all of this was stuff I picked up from one of the Analog Devices blurbs, that PCM was patented in the 20's, and the first digital phone call was between Roosevelt and Churchill, and it was some form of PCM.
ak
She did not developed a protocol. She had the idea of using the same technology used in Player Pianos (basically the the same technology used in Music Playing Jewelry Boxes) to toggle switches for changing frequencies and the filled a patent. I'm not sure it was ever used. It also wasn't digital (though technically it can be used in digital systems). Btw. She was my neighbor for a while.
Interesting site, good books:
http://www.vias.org/albert_ecomm/index.html
Speaking of telegraphs:
http://www.vias.org/albert_ecomm/aec09_telegraph_systems_001.html
ak
http://www.vias.org/albert_ecomm/index.html
Speaking of telegraphs:
http://www.vias.org/albert_ecomm/aec09_telegraph_systems_001.html
ak
