[Closed] Fax machines

Jet Set Willy?

best explain what a fax machine is for the kids

Probably wouldn't handshake in the first place.

The answering fax will go "hi, are you a fax machine" and then ignore if it it doesn't get a sensible answer.

Assuming that you worked around that to force a handshake, and that the datastream was understandable by the fax in terms of data speed (the Spectum cassette wasn't a 'regular' baud rate I don't think), the resultant output would, at best, be gibberish.

It's a bit like asking what'd happen if you spoke Afrikaans to someone whose only language is Russian.

From http://en.wikipedia.org/wiki/ZX_Spectrum_software

The software was encoded on tape as a sequence of pulses that may sound similar to the sounds of a modern day modem. Since ZX Spectrum had only a rudimentary tape interface, data was recorded using an unusually simple and very reliable modulation, similar to pulse-width modulation but without a constant clock rate. Pulses of different widths (durations) represent 0s and 1s. A "zero" is represented by a ~244 ?s pulse followed by a gap of the same duration (855 clock ticks each at 3.5 MHz) for a total ~489 ?s;[11] "one" is twice as long, totaling ~977 ?s. This allows for 1023 "ones" or 2047 "zeros" to be recorded per second. Assuming an even proportion of each, the resulting average speed was ~1535 bit/s.

So the tape would have to be sped up slightly to match a fax's expected 9600bps. But because of the modulation technique, chances are that a fax wouldn't 'hear' anything anyway.

Thinking about it, you might get $something if talking to an old analogue fax. But I don't think it's likely outside of building some sort of custom middleware to specifically try and make it work.

best explain what a fax machine is for the kids

Easiest way to think of it would be a Very poor quality long distance photocopier 🙂