[RTTY] AFSK to FSK converter

[Frank]

I used an AFSK to FSK converted box in the mid 70's to run a model 15 
RTTY machine.

It took the tones from the speaker of the receiver (AFSK)(analog) and 
converted them to digital pulses to drive the printer.  Those pulses 
could just as easily have been used to shift the frequency of an 
oscillator and generate FSK.  OMG they were!  The transmit signal was 
generated by using a relay in the loop of the printer/keyboard to turn 
the digital pulses into FSK.

That AFSK to FSK converted was better known as a TU (terminal unit for 
you novices).

Nowdays we use sound cards to do the same thing

Now anyone want to admit that this entire thread was an April fools joke?

AFSK to FSK converter indeed!

Joe Subich, W4TV wrote:

>
> On 9/17/2012 6:40 AM, Doug Faunt wrote:
> >
>
>> But the K4DSP unit should be simple enough to wire up on perf-board-
>> there are only a dozen components aside from the connectors.
>
>
> The question is whether the K4DSP unit (QST article here for members:
> http://p1k.arrl.org/pubs_archive/139117) will even work with 2Tone.
>
> The developer of 2Tone refuses to adopt a fixed frequency mode - it's
> AFSK only with AFC running all the time.  Since the K4DSP interface
> expects to decode fixed frequency tones (2125/2295 or 1275/1445) how
> well does it work with "drifting" inputs?
>
> The lack of *fixed* inputs may be a serious limitation with any
> regenerator - whether it be the K4DSP design of a simple PLL tone
> decoder:
> www.electroniq.net/radio-frequency/fsk-demodulator-using-lm565.html
>
> 73,
>
>    ... Joe, W4TV
>
>
> On 9/17/2012 6:40 AM, Doug Faunt wrote:
>
>> It's not been mentioned on the RTTY list before, just N1MM-digital, and
>> I'm not getting those emails (not enough bandwidth most of the time).
>>
>> But the K4DSP unit should be simple enough to wire up on perf-board- 
>> there
>> are only a dozen components aside from the connectors.
>>
>> 73, doug
>>
>>
>>> ORIGINAL MESSAGE:
>>> On Mon, 17 Sep 2012 02:41:15 -0400, Doug wrote:
>>>
>>>> Obviously, I've missed something- what's "2 Tone" in this context?
>>>> Google
>>>> isn't being helpful.
>>>>
>>>> 73, doug
>>>
>>>
>>> REPLY:
>>> It's a new program which can replace MMTTY but only with N1MM.
>>>
>>> Check the archives back a week or two.
>>>
>>> 73, Bill W6WRT
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>>>
>>
>>
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