I have a circuit I designed about ten years ago that reliably records and reads back data to/from standard cassette recorders at 2400 baud. It uses CMOS logic and is crystal controlled. The circuit was originally designed to allow me to transfer DATABASE info between some old CP/M machines and IBM PCs. A small adapter cable also allowed me to transfer data from some APPLE computers to IBM PCs that were located in different buildings. Once the audio levels were properly adjusted for the recorder being used, this circuit worked beautifully. I built two of these using wire-wrap. I still have them, though I haven't used them in years. Once we had transferred the needed data I just put them in storage. Oh yes, we did take them out of storage once to use them as a download/upload device for a datalogger, when we didn't have a portable computer available at the moment. So the last time one of them was used was about two years ago. The design is mostly digital, with analog only being used at the RS232 ends. You MIGHT be able to push this to 4800 baud just by changing the crystal to double its present value, but it is the TAPE itself that sets the limit. Ordinary tape can have a certain amount of drop-out, though nowadays you could probably go with a high-end tape with few problems. ----- Original Message ----- From: Nigel Goodwin To: Sent: Friday, February 23, 2001 2:06 AM Subject: Re: [PIC]: Data Recording to Cassette Tape using QPSK. > In message <3A95BA94.9E60B374@spme.monash.edu.au>, Antonio L Benci > writes > >Decoding it may be too much of a challenge. Bit rate is undecided at the > >moment but we're looking at 14.4k as a minimum. > > I don't remember any of the old cassette systems reaching anywhere near > that (nor the Commodore 1541 floppy disks for that matter). The standard > cassette systems used 300 baud, and you could often use a faster system > around 1200 baud - although I think the Sinclair (Timex?) Spectrum was > 1200 baud all the time. > -- > > Nigel. > -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email listserv@mitvma.mit.edu with SET PICList DIGEST in the body