26 May
2006
26 May
'06
2:54 p.m.
Ok, I need some education. On other home type
machines, a standard
shoebox cassette player was used. I assume this is the same on the
PC5150. (This is the cassette interface on the motherboard.)
Yes. On the 5150, there was another 5 pin DIN socket next to the keyboard
connector. The pinout was the same as a TRS-80 (M1, M3, M4, Coco)
cassette connecotr, and you were, apparently, supposed to buy a cable and
recorder from the local Radio Shack.
The data format is in the techref (I've typed it into this list several
times, it should be in the archives!). At the bit level it's very similar
to the TRS-80 1500 baud scheeme (!).
What would be an example of a different setup?
Well, the HP9830 for one. It uses a Compact Cassette containing a tape
with a higher (I think) coercivity. The whole width of the tape is used
in one direction (you don't flip the tape over to record the other side).
Two tracks are recorded on the tape -- a flux transition on one of them
is a '1' bit, a flux transtion on the other is a '0' bit, and transitions
on both tracks simultaneously is a byte marker.
Some machines used similar tapes, but recorded a clock and data track in
each direction.
Amongst other devices to use 'digital' cassettes are the Facit 4208 (an
RS232-interefaced tape drive), DEC TU60, Some Philips thing that I forget
the number of (P830????), and an option for the Texas Silent 700
terminal. The latter was a chassis that mounted on top of the Silent 700
and contianed 2 cassette drives and control electronics. They were
intended as a replacement for paper tape -- you could record onto either
tape from the line or from the keyboard, play either tape back to the
line or printer, copy from one tape to the other, etc.
-tony