[2][3] Starting in 1961, Philips (in conjunction with Grundig) began work in its Vienna tape production facilities, on a (HiFi)-compatible single-hole cassette.

Philips' management finally gave preference to this development, but informed its partner Grundig rather late, which led Grundig - who received an offer to participate in the Pocket Recorder, to abandon the DC-International cassette it developed without further ado.

This was based upon construction drawings of the compact cassette, which Grundig had taken after their negotiations with Philips.

[2][4][5] For a 90-minute DC-90 cassette (45 minutes per side), the tape length is 137 m with a triple play band (PES 18, thickness 0.018 mm).

For a 120-minute DC-120 cartridge (60 minutes per side), the tape length is 185 m with quadruple play band (PES 12, thickness 0.012 mm).

At its launch, there were 25 pre-recorded music cassettes from Telefunken, Decca and RCA Victor available.

These recordings on the cassettes ranged from country music to The Rolling Stones, the playing time is about 30 minutes per side.

[2] For home recordings, unrecorded, blank cassettes were available from Grundig, Telefunken, BASF and Agfa-Gevaert.

[6] Several portable cassette tape players were made using transistor technology and for installation in a motor vehicle.

[7][3] At the launch of the DC-International, pre-recorded cassettes from Telefunken, Decca, and RCA Victor were available.