James Davis
2017-09-16 19:49:46 UTC
Hi all, Jorge and Oliver, and everyone interested in a poor-man's ADT:
I get the impression, from reading the reverie in "What did an original Apple II sell for?" that it may be possible to use the Apple II Cassette port to do Disk Transfers to/from other PCs at a much higher rate than what is currently possible with ADT, if one reduces the resistance of the Cassette-Output resistor (R19 on an Apple II/II+ and R6 on an Apple IIe/Enhanced IIe).
Is this so?
And, is it just one way (on the output) or will it work both ways?
And, only with Apple II's and/or Mac's?
Or, will it work between Windows PC's and Apple II's, also?
And, at what (much higer) rate?
Also, could it be used as I/O into/out-of an RS232 TO USB adapter/converter?
Or, is this idea overkill and unnecessary?
I calculated that a resistance of 100.84 ohms in parallel with the 12 K-ohm Cassette-Output resistor would bring the total resistance down to 100 ohms, the same as the resistance to ground on the bottom side of the cassette output circuit, thus balancing the signal halfway between zero and five volts (0v~5v) DC. So, a 100~101 ohm, 1/4~1/2 watt, +/- 5%, resistance would probably work best to fairly balance the circuit.
Then, with the right software on both ends, one could do Apple Disk Transfers just as fast or faster than with an SSC/RS232 rig. Although, I did read that this all might be limited to 19 K-baud, because of the maximum speed of reading from and writing to floppy disks. But, with write verification, this might be increased or decreased in speed, depending on the media used (e.g., 5.25" floppies, 3.5" floppies, or Hard Disks).
What do you all think? Can it be done? And, Why or Why not?
James Davis
I get the impression, from reading the reverie in "What did an original Apple II sell for?" that it may be possible to use the Apple II Cassette port to do Disk Transfers to/from other PCs at a much higher rate than what is currently possible with ADT, if one reduces the resistance of the Cassette-Output resistor (R19 on an Apple II/II+ and R6 on an Apple IIe/Enhanced IIe).
Is this so?
And, is it just one way (on the output) or will it work both ways?
And, only with Apple II's and/or Mac's?
Or, will it work between Windows PC's and Apple II's, also?
And, at what (much higer) rate?
Also, could it be used as I/O into/out-of an RS232 TO USB adapter/converter?
Or, is this idea overkill and unnecessary?
I calculated that a resistance of 100.84 ohms in parallel with the 12 K-ohm Cassette-Output resistor would bring the total resistance down to 100 ohms, the same as the resistance to ground on the bottom side of the cassette output circuit, thus balancing the signal halfway between zero and five volts (0v~5v) DC. So, a 100~101 ohm, 1/4~1/2 watt, +/- 5%, resistance would probably work best to fairly balance the circuit.
Then, with the right software on both ends, one could do Apple Disk Transfers just as fast or faster than with an SSC/RS232 rig. Although, I did read that this all might be limited to 19 K-baud, because of the maximum speed of reading from and writing to floppy disks. But, with write verification, this might be increased or decreased in speed, depending on the media used (e.g., 5.25" floppies, 3.5" floppies, or Hard Disks).
What do you all think? Can it be done? And, Why or Why not?
James Davis