Commodore Datassette

The Commodore 1530 (C2N) Datassette (a portmanteau of data + cassette), was Commodore's dedicated computer tape recorder. It provided access to an inexpensive storage medium for Commodore's 8-bit home/personal computers, notably the PET, VIC-20, and C64. A physically similar model Commodore 1531 was made for the Commodore 16 and Plus/4 series computers.

Description and history

The Datassette contained built-in A/D converters and audio filters to convert the computer's digital information into analog sound and vice versa (much like a modem does over a telephone line). Connection to the computer was done via a proprietary edge connector (Commodore 1530) or mini-DIN connector (Commodore 1531). The absence of recordable audio signals on this interface made the Datassette and its few clones the only cassette recorders usable with CBM's machines, until aftermarket converters made the use of ordinary recorders possible.

The inexpensive and widely available audio cassettes made the Datassette a good choice for the budget-aware home computer mass market. In Europe (especially in the United Kingdom), the Datassette was the medium of choice for several years after its launch, although floppy disk drives were generally available. In the U.S., however, disk drives quickly became standard, despite the Commodore 1541 floppy drive costing roughly 5 times as much as a Datassette.

The Datassette was very slow (transferring data at around 50 bytes per second) but relatively reliable storage medium, due to the unique Commodore recording format. Contemporary disk drives were an order of magnitude faster and more reliable. Some years after the Datassette's launch, however, special "turbo tape" software appeared, providing much faster tape operation (loading and saving). Such software was integrated into most commercial prerecorded applications (mostly games), as well as being available separately for loading and saving the users' homemade programs and data. These programs were only widely used in Europe, as the US market had long since moved onto disks.

Datasettes could typically store about 200 KB (100+ KB per 30 minute side, [http://starbase.globalpc.net/~vanessa/hobbies/commodore-info.html] ).

Main models

Used with the PET, VIC-20, C64/128

There are at least four main models of the 1530/C2N Datassette, listed chronologically below. The first two external models were made as PET peripherals, and styled after the PET 2001 built-in tape drive. The latter two were styled and marketed for the VIC-20 and C64. All 1530s were compatible with all those computers, as well as the C128.
*The built-in Datassette in the original PET 2001: black cassette lid, five white keys, no tape counter, no SAVE LED
*Black body original shape model, black cassette lid, five black keys, no tape counter, no SAVE LED
*White body original shape model, black cassette lid, five black keys, with tape counter, no SAVE LED
*White body new shape model, silver cassette lid, six black keys, with tape counter and a red SAVE LED

In addition to this, some models came with a small hole above the keys, to allow access to the adjustment screw of the tape head azimuth position. A small screwdriver could thus easily be used to affect the adjustment without disassembling the Datassette's chassis.

Confusingly, the Datassette at various times was sold both as the "C2N DATASETTE UNIT Model 1530" and as the "1530 DATASSETTE UNIT Model C2N". Note the difference in spelling (one versus two "s" 'es) used on the original product packaging.

Used with the C16/116 and Plus/4

Similar in physical appearance but incompatible in connector format with the 1530/C2N models is the Commodore 1531, made for the Commodore 16 and Plus/4 series computers.
*Black/Charcoal body new shape model, silver cassette lid, six light gray keys, with tape counter and a red SAVE LED

Through the use of an adaptor, it could be used with a C64/128.

External links

* [http://www.xs4all.nl/~lagendr/Menu/DATS.htm Similar Commodore tape drives]
* [http://www.zimmers.net/cbmpics/dtapes.html Datasette photos]
* [http://www.zimmers.net/anonftp/pub/cbm/crossplatform/transfer/C2N232/ Description of tape format with conversion utilities and code]
* [http://www.ktverkko.fi/~msmakela/8bit/c2n232/index.en.html C2N232 project] to build a hardware adaptor/software program to archive Commodore Datassette files to a modern computer.
* [http://www.luigidifraia.com/c64/dc2n/index.html DC2N Homepage] Digital C2N replacement project.