Quote:
Originally Posted by DMcMahon
I also used cassette recorders to record and load programs for my expanded Nascom 1.
The default speed of 300 baud was dismally slow so I upgraded the tape interface to a Cottis/Blandford high speed interface (basically copying a construction article in Wireless World I think).
Getting it to run reliably at 2,400 baud was tricky, found it ran best using my only Hi -Fi deck at the time a Aiwa 1250, on a good day could get it to run at its max speed of 4,800 baud.
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There were a number of different recording-digital-data-on-tape 'standards' around back then; one I remember was called Tarbell -
https://en.wikipedia.org/wiki/Tarbel...ette_Interface - the othes I remember were the Computer User Tape System [CUTS] and the Kansas City standard.
There were lots of circuits for these published in "Byte" nagazine back then, using variable degrees of PLL-style decoding and raw bit-banging in the processor. I remember building one that used the 1200-baud Bell-202 modem tones, which subsequently resurfaced in VHF/UHF AX25 packet-radio service - indeed I demonstrated AX25 packet-radio to someone using off-air recordings stored on cassette!