It is amazingly clever! That FIFO with the moving reader head is pretty
unique!

All those stepper switches to put a message number on the tape are
interesting and complicated!

I just thought they'd put a header on the tape during its original
perforation. That header would be the destination, probably as a numeric
sequence that would indicate the routing at each relay station.

Years ago, I remember seeing the printer and reperf at my college
newspaper. This used 6 bit TeleTypesetter code. At the start of each story
on the printer was a line of overprinted garbage. But, on the tape, it
showed up as a dot matrix human readable story number. When the editor
found a story on the printer that he/she wanted to use, they'd zip back
through the tape looking for the story number as readable holes in the
tape. I always thought (and still do) that was very clever. I could see
something like this in torn tape relay where the routing of the message
would just be a series of numbers punched as a dot matrix bitmap.

On the ping pong transmit, it seems like there would have to be an opertor
there loading the tapes. If each new tape could be spliced to the end of
the oldest one, an opertor would only need to be there to splice on the
new message.

All amazing stuff!

Harold
https://w6iwi.org

On Thu, July 23, 2026 5:54 pm, Nick England wrote:
> Actual torn tape relays used two TDs per outgoing line. They ran in
> ping-pong fashion so you could load one while the other was transmitting.
> Here’s mine in operation.
> https://m.youtube.com/watch?v=FRdK8ZvXNcI&ra=m
>
>
> The sequentially numbered message header is inserted via stepper relay in
>  this model. Earlier versions used an additional TD with a sequential
> header tape.
>
> At the receiving end, a reperf/TD tape FIFO set could be used.
> Here’s mine
> https://m.youtube.com/watch?v=XD97YVIaPlA&ra=m
>
>
>
> I love torn tape relay!!
>
>
>
> Nick England K4NYW
> Chapel Hill NC
> www.navy-radio.com
>
> On Thu, Jul 23, 2026 at 7:49 PM Harold Hallikainen via GreenKeys <
> greenkeys@mailman.qth.net> wrote:
>
>>
>> …,,,,,,,Instead, the line could continuously handle "tape speed." And,
>> to me, torn tape relay is an early form of packet switching.
>>
>> A question on torn tape relay, when a new tape segment was passed to be
>>  transmitted, was it spliced to the tape currently being transmitted so
>> the line would never sit idle, and no operator needed to load the next
>> tape? This, of course, is a FIFO buffer that handles bursty traffic
>> input and provides continous output.
>>
>> Harold
>> https://w6iwi.org
>>
>>
>>
>>
>


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