Vaisala SPT11A reader (was Data General Nova Star Trek)

Erik Baigar erik at
Sat Apr 30 08:34:21 CDT 2016

On Tue, 26 Apr 2016, Paul Birkel wrote:

> Thanks Erik; very helpful.  For reference, mine also shares the same
> firmware revision.  Can you share your source code as well?

Upon request I added the firmware files to operate the SPT11A paper tape
reader (together with the source code, V1.01, sdcc) to the special
service section on my server:

Use is without warranty and at own risk - credits and link to
my pages are welcome   ;-)



> -----Original Message-----
> From: Erik Baigar [mailto:erik at]
> Sent: Tuesday, April 26, 2016 5:33 AM
> To: Paul Birkel
> Cc: jwsmail at; cctalk at; shermanfoy at
> Subject: Vaisala SPT11A reader (was Data General Nova Star Trek)
> Dear Paul,
> thanks for your email - I acquired the reader several years ago and did
> quite a lot of experiments to figure out how to use it with the original
> firmware SPTS11, 2.02, 5289 but I never got an answer from the reader. So
> the project of Jim to read in the DG tapes was the reason I needed to
> address this issue. For your (and the communities) convenience I placed the
> original firmware (27C256 type EPROM)...
> ...and my new one (also 27C256)...
> ...onto my server. My new firmware just sends out the data read via the
> serial port at 9600, 8N1. A welcome messages tests the serial communication
> on starting and during this time the red LED is on.
> On getting ready the green LED takes over and the yellow one shows the state
> of the sprocket input: For each byte read this LED flashes. At 9600 the
> serial port is always faster than you can pull the tape through the reader,
> so I do not expect the red LED (indicate a buffer overflow, byte lost) come
> on during normal operation...
> The pinout of the Sub-D9 male plug is as usual on serial ports:
> 5: GND, 2: Data from reader to PC, 3: Data from PC to reader (not used in my
> firmware, but original expects some start/config command here) additionally
> 7: DC input to reader (in my case 9V).
>    Hope this helps,
>       best regards,
>          Erik.
> On Tue, 26 Apr 2016, Paul Birkel wrote:
>> Eric;
>> Would you please share your firmware updates, and any other
>> information that you've gleaned regarding the Vaisala SPT11A reader?
>> I recently acquired one of these as well but haven't yet started on
>> reverse-engineering it into something useful  Would prefer to leverage
>> your experience, if you please :->.
>> Good health to You and Yours!
>> paul
>> (from Maryland, USA)
>> -----Original Message-----
>> From: cctalk [mailto:cctalk-bounces at] On Behalf Of Erik
>> Baigar
>> Sent: Monday, April 25, 2016 11:42 AM
>> To: jim s; cctalk at
>> Cc: Sherman Foy
>> Subject: Re: Data General Nova Star Trek
>> Hi Jim,
>> regarding reading the StarTrek paper tapes I spent some time on the
>> weekend to rework my SPT11A manual reader - I got this from an eBay
>> auction and it was an accessory for some military receiver (probalby
>> to read in some codes). It had a fimrwaere which refused to
>> communicate with a simple terminal program, so I reverse en- gineered
>> the hardware and replaced the original ROM it by an own firmware which
>> simply sends the contents read from PPT to the PC via its RS232C...
>> So I'd offer sending this to you as an item on loan to read in your
>> tapes and you return it afterwards? I tested it with some data and it
>> works well (just slowly pull the paper tape through the reader and use
>> e.g. putty to log the binary serial output). After turning on the
>> reader there is a short welcome message to verify the serial connection
> (9600,8N1).
>> The only question is, whether you can handle the EU style power supply
>> shown in the picture...
>> I ordered USB->RS232C converters and if you have some more time, I'd
>> attach one of them to the reader not only doing conversion but also
>> supplying the converter with power from the PC.
>> Addidionally you should send me your physical address via PM so I can
>> prepare for shipping...
>>    Best regards from Germany,
>>       Erik.
>> -----

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