[GreenKeys] Model 19 on ITTY

[Duncan Brown]

AL,

Are XR-2211 chips still available?  They make a very simple AFSK 
decoder. It is a 14 pin DIP IC and with a few Rs & Cs will give you an 
AFSK decoder. (you don't need any limiter or selectivity coming off 
ITTY) Then just add an optocoupler to interface with the TTY loop.

If you you manage to get MMTTY to  output to a serial port, don't worry 
about ASCII  conversion. MMTTY will output in 5-bit.

For a serial port, look for an old Win 7 or XP laptop.

Good luck,

Duncan
K2OEQ


On 1/24/2020 09:56, Al Klase wrote:
> Hi Ralph, /et al/
>
> The point is we don't have a TU.  We'll be running a PC anyway if we 
> monitor ITTY.  Logic level to current loop isn't a problem, and I've 
> found an Arduino "sketch" that will go from ASCII to baudot.
>
> I'm exploring RTTYT which looks like it will handle the PC chore.  The 
> scheme is complicated by the fact that modern PC's don't have RS-232 
> ports, and the UART's in the USB dongles don't support 5-bit formats.
>
> 73,
> Al
>
> On 1/23/2020 5:00 PM, Ralph Mowery wrote:
>>
>> Doesn’t the audio come out of your computer speakers ?   If so you 
>> could just run that audio into any modem/TU and then to the machine.  
>> I think that is what I did a year or so back.
>>
>> Ralph ku4pt
>>
>> *From:*greenkeys-bounces at mailman.qth.net 
>> [mailto:greenkeys-bounces at mailman.qth.net] *On Behalf Of *Al Klase
>> *Sent:* Thursday, January 23, 2020 4:40 PM
>> *To:* greenkeys at mailman.qth.net
>> *Subject:* [GreenKeys] Model 19 on ITTY
>>
>> Gang,
>>
>> We're still klutzing around with TTY's at the Radio Technology 
>> Museum, and we're starting to make some progress.  So, how do we get 
>> data from ITTY out to the machine?
>>
>> I have MMTTY copying the stream FB, but don't see the hooks to get 
>> the data out.  Even 8-bit ASCII on a COM Port would be OK, as we can 
>> use TinyFSK on an Arduino to get to Baudot.
>>
>> I may just be dense. :-(
>>
>> Al
>>
>
> -- 
> Al Klase – N3FRQ
> Jersey City, NJ
> http://www.skywaves.ar88.net/
>
>
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