Southwest Novation Apple Cat II Modem: $500

[pbirkel@gmail.com]

Hi,

60 BAUD is a thing, just not common to the general public. The specs for my modem are listed to operate from 60 BAUD to 600 BAUD ...

Cite your online source, please. Inquiring minds ...

 

[wperko]

Cite your online source, please. Inquiring minds ...

Hi,

Modems that support speeds from 60 BAUD to 600 BAUD are typically categorized as early analog modems. One example is the Bell 103 modem, which was one of the earliest commercially available modems. It operated at speeds ranging from 300 bits per second (BPS) to 1200 BPS, but it could also operate at lower speeds like 60 and 75 BPS. Another example is the Bell 113 modem, which operated at speeds from 110 BPS to 300 BPS. These modems were primarily used in the 1960s and 1970s for transmitting data over telephone lines.

http://www.s100computers.com/Hardware%20Manuals/PMMI/pmmi-mm-103-modem-and-comm-adapter.pdf

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[pbirkel@gmail.com]

So given the defined counter chain in the PMMI MM-103 the lowest baud rate achievable is actually 61.27; the documentation states "61" as the lowest rate. Arbitrary rates are of course achievable with arbitrary counter chains :->. Interoperability across-the-wire would require group consensus, but I can imagine a two-station pair attempting to coax a higher rate based on the quality of their wire-line. If the TELCO has provisioned a dedicated low-noise balanced wire-pair I can imagine being able to push the rate significantly higher than otherwise. Don't know how much RTTY tried to push-the-envelope given multipath effects.

Can't find any documentation for either the Bell 101 or 103 regarding reducing their baud rate below their design intent (110 and 300 baud respectively).

https://en.wikipedia.org/wiki/List_of_device_bandwidths rather arbitrarily chooses "50 baud" for "teleprinter", whereas https://en.wikipedia.org/wiki/Teleprinter make clearer the range of standard rates and the causes for limited rates in RTTY (Navy life I expect :->).

 

[wperko]

So given the defined counter chain in the PMMI MM-103 the lowest baud rate achievable is actually 61.27; the documentation states "61" as the lowest rate. Arbitrary rates are of course achievable with arbitrary counter chains :->. Interoperability across-the-wire would require group consensus, but I can imagine a two-station pair attempting to coax a higher rate based on the quality of their wire-line. If the TELCO has provisioned a dedicated low-noise balanced wire-pair I can imagine being able to push the rate significantly higher than otherwise. Don't know how much RTTY tried to push-the-envelope given multipath effects.

Can't find any documentation for either the Bell 101 or 103 regarding reducing their baud rate below their design intent (110 and 300 baud respectively).

https://en.wikipedia.org/wiki/List_of_device_bandwidths rather arbitrarily chooses "50 baud" for "teleprinter", whereas https://en.wikipedia.org/wiki/Teleprinter make clearer the range of standard rates and the causes for limited rates in RTTY (Navy life I expect :->).

Hi,

Now you're nit-picking between 60 and 61? $14.99 and $15 ... they're both $15 out of your pocket. The idea of 60 to 600 is that the modems are IN THAT RANGE.

The accuracy of how those modems worked in the old days is why there was enough "slop" so one system off a little on the voltages and frequencies could still communicate with another system off a little on the voltages and frequencies.


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[pbirkel@gmail.com]

Now you're nit-picking between 60 and 61? ... The idea of 60 to 600 is that the modems are IN THAT RANGE.

Not at all. Just keeping the record straight. I don't think that we want to add errors-of-fact to the public conversation, "muddying the waters" as it were.

WRT "IN THAT RANGE", then by your implied definition of "in range" then 600 baud would be excluded if you're excluding 60 baud from "in range". It's clearer to simply report the actual minimum and maximum baud rates supported, full stop :-}. 60 baud wasn't one of them in the case of the MM-103.

It's certainly true that Baud Rate Generator ICs produced rate-errors of up to 3.125 percent, although most rate-errors were fractional-percent. Here are two typical tables; note the anomalous duty-cycles in both tables (asterisk indicates "When Duty Cycle is not exactly 50%, it is 50% ± 10%.").

 

[wperko]

Not at all. Just keeping the record straight. I don't think that we want to add errors-of-fact to the public conversation, "muddying the waters" as it were.

WRT "IN THAT RANGE", then by your implied definition of "in range" then 600 baud would be excluded if you're excluding 60 baud from "in range". It's clearer to simply report the actual minimum and maximum baud rates supported, full stop :-}. 60 baud wasn't one of them in the case of the MM-103.

It's certainly true that Baud Rate Generator ICs produced rate-errors of up to 3.125 percent, although most rate-errors were fractional-percent. Here are two typical tables; note the anomalous duty-cycles in both tables (asterisk indicates "When Duty Cycle is not exactly 50%, it is 50% ± 10%.").
View attachment 1275115

Hi,

Now you are introducing "evidence" from some other source? All I said was there are modems that support 60 to 600 BAUD. My PMMI manual corrected me at 61 BAUD to 600 BAUD ... that along with phone line errors , voltage and frequency errors I am sure is included in that 61-600 BAUD statement.

These are vintage computer modems, not modern fixes. Getting anal over the BAUD rate is NOT changing my statements.



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[pbirkel@gmail.com]

Peace :-}.

 

[syzygy]

Your honor, If it pleases the court, I would like to place into evidence this Amicus Brief including a TONE RECEIVER PCB CIRCUIT BOARD. I call your attention to the component containing a clear label that includes "60 BAUD". While not a Novation Apple Cat II Modem, we offer this evidence, under the international laws of MODulation and DEModulation to assert that 60 BAUD is, indeed, a thing - we offer no position on the current significance of, or further explanation of what kind of thing, and only assert that it is a thing.

 

[smbaker]

Your honor, If it pleases the court, I would like to place into evidence this Amicus Brief including a TONE RECEIVER PCB CIRCUIT BOARD. I call your attention to the component containing a clear label that includes "60 BAUD". While not a Novation Apple Cat II Modem, we offer this evidence, under the international laws of MODulation and DEModulation to assert that 60 BAUD is, indeed, a thing - we offer no position on the current significance of, or further explanation of what kind of thing, and only assert that it is a thing.

But... it also says 965 HZ, which if we assume a 16X divisor could actually be 60.31 Baud.