TED

MOS Technology TED (7360/8360)

Overview

The MOS Technology TED (Text Editing Device) is a combined video and sound chip developed for Commodore's budget line of 8-bit home computers in the mid-1980s. Rather than pairing separate video and audio chips as the Commodore 64 did with the VIC-II and SID, Commodore integrated both functions into a single chip to reduce manufacturing costs for its more affordable machines.

The TED chip powered the Commodore 16, Commodore 116 and Commodore Plus/4, computers aimed at entry-level users and the education and business markets rather than at gamers. As a result, the TED's sound capabilities were considerably simpler than those of the SID chip used in the C64, reflecting its role as a cost-conscious, general-purpose chip rather than a dedicated music synthesizer.

Unlike the SID's rich, semi-analogue synthesis engine, the TED's audio section is a straightforward digital sound generator. It offers only two independent sound channels, with no dedicated envelope generator, no filter, and a much narrower set of waveforms. This made it far less flexible for expressive music, but its simplicity also made it easy to program and predictable in behaviour across all units, without the manufacturing variance that gave the SID its inconsistent, characterful sound.

Despite its limitations, the TED found a small but dedicated following among musicians and demoscene programmers on the Plus/4 and C16, who developed techniques to extract as much musical expression as possible from its restricted feature set.

Technical characteristics

• Manufacturer: MOS Technology
• Model: 7360 / 8360
• Channels: 2
• Synthesis: Fully digital sound generation
• Waveforms: Square wave (channel 1 and 2), white noise (channel 2 only)
• Envelope: None (volume control only, no ADSR)
• Filter: None
• Additional function: Also handles video output (text and graphics modes)
• Computers: Commodore 16, Commodore 116, Commodore Plus/4

TED and tracker music

Music on the TED never reached the scale or sophistication of the C64's SID scene, largely because the Plus/4 and C16 sold in much smaller numbers and attracted a smaller base of programmers and musicians. Nonetheless, a committed community formed around these machines, particularly in regions such as Central and Eastern Europe where the Plus/4 saw stronger adoption.

Because the TED lacks a hardware envelope generator, composers had to simulate volume envelopes entirely in software, manually adjusting channel volume on every frame to fake attack, decay and release effects. This placed a heavier burden on the CPU compared to SID composition, where envelope shaping was handled directly by the chip.

With only two channels and no filter, TED musicians relied heavily on rapid arpeggios, channel-sharing tricks and creative use of the noise channel for percussion to approximate the fuller, more layered sound that three SID voices could produce. Dedicated trackers and music routines were built specifically around these constraints, and a small but active scene continues to produce new TED chiptunes today, valued for their distinctively sparse and raw character compared to SID music.

Further reading

• MOS TED 7360/8360 documentation