View Full Version : Cassette drive that warns not compatible with commodore or atari?

September 16th, 2009, 12:40 PM
So unfortunately I didn't get much info off the unit but found something that struck me as odd. It was an external cassette drive, longish version with counter and several controls. On the left side it had it's output (3? pins that went to I think 2 3.5mm plugs), a circle adapter power plug and some sideways power plug (I guess you could pick from either).

It says on the unit (sticker type thing) it's designed to be compatible with most home computers (EXCEPT Atari and Commodore systems).

Is it really that different? Besides the IBM what common home computer would they be talking about? I couldn't tell if it worked, it did take batteries too as a power option. I didn't pick it up although it had the plugs which were probably worth the cost of the unit but my collection as far as cassette use has mostly Commodore and Atari systems.

I guess I'm just surprised, I thought cassette tapes were much more universal.

September 16th, 2009, 01:13 PM
Actually, the cassette recorders *are* pretty interchangeable. The only exceptions bieng Atari and Commodore. Atari cassette drives use SIO, and Commodore tape drives use a special TTL level interface. In both cases, reliability is greatly improved by moving the digital to analog convertion to the cassette drive itself, rather than having it in the computer. The computer simply sends a serial signal to the drive, and the drive records it. On playback, the drive reads the analog signal from the tape, converts it to digital, and sends the signal back. No volume controls or tone controls to mess with.

Other computers (TRS-80, original IBM PC, TI-99/4A, Apple II, etc) all used standard audio cassette recorders. The computer generates an analog tone, and it's recorded to the cassette. The user needs to be mindful of the volume control setting on the recorder, and any tone controls present. Similarly, when played back, the recorder needs to be set right - too high a volume, or too low, and the computer might not be able to decode it.

So, yeah, what you have is little more than a portable cassette recorder - so it's compatible with everything... except the computers that used something special.


September 16th, 2009, 05:16 PM
Don't forget all the European and Japanese home computers: anything from ZX Spectrum, BBC Micro and Oric to MSX systems and much more. They all use regular cassette recorders.

Actually there is at least a third system using custom tape recorders, namely the Spectravideo SVI-318/328 series. I think the latter SVI-728/738 do too, despite being part of the MSX standard.