What we know
In the last few years, a lot of useful information has appeared about the secrets of DCC. Old magazine articles, press conference handouts, course material for technicians who needed to repair DCC recorders, service manuals and service bulletins, and datasheets have shown up on the Internet in digital form, and the DCC Museum has managed to get in contact with several people who worked on DCC behind the scenes.
At this point, I'm not sure what the question is, but here are a couple of answers:
- Philips mentions three generations of DCC recorders. They refer to the DCC-730 and DCC-951 from 1994 as the "Third Generation", with Turbo Drive and the ability to record song titles as distinguishing features.
- The "first generation" was obviously the DCC-900 which was the first DCC recorder that came out in 1992. Several other manufacturers released recorders at the same time, which were all very similar to the DCC-900 on the inside. Marantz made two recorders that have a better D/A converter (TDA1547) and RadioShack sold the Optimus DCT-2000 which was designed by RCA but had Philips plugin boards and a Philips mechanism.
- The "second generation" must then be what came in between: Philips released quite a number of DCC recorders in 1993 that were all based on the same hardware: The DCC-600, DCC-300, DCC-380 and DCC-450 (aka DCC-91) all have the same circuit boards inside but there are small variations (e.g. with remote control buses populated or not) and enclosures are different sizes.
- The first and second generation recorders use the same chipsets (the first portable players used a different chipset). The third generation uses a different chipset.
- The third generation chipset is more integrated that the first generation chipset. Modulation, demodulation, tape formatting and error correction are all done in a single chip in the third generation chipset.
- For the first generation chips, there is almost no documentation, but the third generation chipset is very well documented. The datasheets are also clearly not just intended for technicians who merely need to understand why a recorder might have stopped working and how to repair it. They contain enough data to (theoretically) connect the chips together, slap them on a cassette mechanism with an MR head assembly and hook up a microcontroller to build your own DCC recorder. Just a few pieces of information are missing such as the format of the information that gets stored as SYSINFO (the data that is interleaved with the audio data) and AUXINFO (the data that's on the 9th track).
- The DCC-175 was a portable recorder that was only available in the Netherlands. It could be connected to a Windows 3.1 or 95 or 98 PC with a special "PC-Link" or "DCC-Link" cable (naming is inconsistent). The cable was plugged into the parallel printer port and used a custom chip by Philips Key Modules for which no documentation is available. We know from a somewhat reliable source that only 1400 of these cables were made, and they are extremely rare at the time of this writing.
- The DCC-175 and the PC-Link cable made it possible to copy music (in PASC format) from tape to hard disk and vice versa, and it could backup data files too, at the same 384kbps per second (which was rather slow even for 1995, by the way). It also allowed some light editing (copy-paste music fragments, play loops, place markers, change volume and fade in/out, change filter parameters, create compilation tapes).
- In the late 1990s, someone started a reverse-engineering effort on the DOS backup tape driver that's included with the PC-link cable and found out that the hardware appears very similar to a parallel port tape interface by Shuttle Technologies. The reverse-engineering project was never finished, though.
- The schematics in the DCC-175 reveal that the PC-link connection is directly connected to a 5V power supply in the recorder, a bidirectional synchronous serial port of a microcontroller in the recorder, and the...